Effects of dietary inclusion of sugarcane (saccurum officinarum) filter cake on the performances of broiler chickens

Abstract

This study evaluated the feed value of sugarcane filter cake (SFC) for broilers. A total of 336 one-day-old Cobb500 were randomly allotted to seven treatments (T) with three replications. A diet without SFC (T0, control) was formulated for the starter (1–14 days), grower (15–28 days) and finisher (29–49 days) phases. The test diets contained sun-dried SFC at two levels (5% and 10%) and varied with feeding periods [(5%SFC (T1)- and 10%SFC-based diets (T2) for the entire period, 5%SFC (T3)- and 10%SFC-based diets (T4) for grower to finisher phases and 5%SFC (T5)- and 10%SFC-based diets (T6) for finisher phase]. Feed intake (FI), final body weight (FBW), total body weight gain (TBWG) and feed conversion ratios (FCR) were not affected (P > 0.05) at the starter phase. However, FI and ADG on 10%SFC diets were reduced (P < 0.05) at the grower phase. ADG and FBW (P < 0.05) were higher for the 10%SFC diet at the finisher phase. No performance differences (P > 0.05) were observed for the finisher and entire periods on 5%SFC-based diets. The overall FI, ADG and FCR did not vary among treatments (P > 0.05) however, TBWG was highest in T5 and T6. The overall feed consumption ranged from 3.86–4.26 kg/bird (P > 0.05). Treatments did not differ in dressed and eviscerated carcasses, cut parts, visceral organs and meat-to-bone ratios (P > 0.05). The 5%SFC- and 10%SFC-based diets resulted in higher net income. In conclusion, up to 10%SFC inclusion in the broiler diet for the whole period or at the finisher phase increases performances and economic benefit.

Keywords:

• Sugarcane filter cake
• Broiler performances
• Economic benefit

1. Introduction

Poultry as a livestock subsector contributes, at large, to the livelihood of people through sourcing foods (eggs and meat), generating income and creating employment opportunities. The demand for animal-source food is ever-increasing in Ethiopia, which has been driven by increased human population, urbanization, income and changes in lifestyle (Getachew et al., 2018). However, the current level of poultry production and product supply is not matching the demand, often rating the country below that of the neighboring countries in consumption. There are various production challenges that hinder the development of commercial poultry sector in the country, where feed is most important. In Ethiopia, feed cost accounts for 75–80% of the total operational costs of livestock production in general and poultry production in particular (Demissie, 2017). The market price of compound poultry feed has considerably increased due to inadequate production, accessibility and availability of major feed ingredients and an inefficient marketing system, souring the price of chicken products (Demissie, 2022). It is particularly important for emerging small- and medium-scale commercial poultry farms. According to Demissie (2022), the price of major feed ingredients (maize, soybean meal, wheat middling, noug seed cake, wheat bran, groundnut cake and linseed cake) increased by 112.5 to 627.3% during the last five years (2016/17 to 2020/21) with a parallel increase in the price of compound feed of layer, broilers and chicks by 85.5,80, 89.6, 110.8%, respectively (Demissie, 2022). Besides, the use of cereal grains for livestock feeding is influenced by its limited production, availability, increased cost of production and stiff competition for human consumption. It is, therefore, crucial to economize poultry rations by incorporating locally available and nutrient-reach alternative feed ingredients to minimize production costs and maximize profit.

The use of numerous non-conventional feed resources available in the country such as sugarcane filter cake (SFC) is marginalized. Sugarcane filter cake (also called sugarcane mud, sugarcane press residue or filter press cake) is a residue generated during the sugar purification at the sugar factories (Suresh & Reddy, 2011). It is a soft, spongy, amorphous and dark brown to brownish in color, making 3–4 percent of sugarcane processed by the factory’s mill (Genetu, 2018; Gupta et al., 2011). In Ethiopia, SFC is often left unprocessed and used as a soil conditioner in the sugarcane fields (Genetu, 2018). However, a large part of it is still wasted and accumulated in sugar industries, competing for storage space and posing environmental pollution.

A range of studies (Bhosale et al., 2012; Dhas, 2016; Kumar et al., 2015; Sahu et al., 2016; Saleh-E-In et al., 2012; Suma et al., 2007; Suresh & Reddy, 2011) have shown SFC as a potential source of organic and inorganic nutrients, being moderate in crude protein and fiber, but reach in soluble sugar and minerals (e.g., calcium and phosphorous). It is also a good source of saturated and unsaturated fatty acids (Sahu et al., 2016; Suresh & Reddy, 2011). Studies have also revealed that the inclusion of SCF in broiler and layer diets had a positive effect on carcass and egg yield and quality, where the young and adult birds tolerated up to 3% and 15% inclusions in the diet (Budeppa et al., 2008; Dhas, 2016). Furthermore, its benefit for the strength of broiler bone is well documented (Suresh, 2007).

According to Genetu (2018), about 1.6 million tons of SFC was produced by sugar industries in Ethiopia in 2017. With the current expansions and new sugar estates establishments in the country, the production and availability of SFC are expected to be more, indicating its potential use for livestock feeding. Despite SFC being a feed resource for livestock in some other developing countries, its feed use in Ethiopia is negligible. Only, limited studies have indicated the chemical composition of SFC produced in Ethiopia. Hence, it is important to conduct animal feeding trial and validate performances on SFC-based diets before directly adoption literature-based recommendations. This study aimed to evaluate the effect of sun-dried SFC inclusion in the diet of broiler chickens on feed intake, growth performance carcass characteristics and economic benefit.

2. Materials and methods

2.1. Study area

The study was conducted at the poultry farm of Debre Zeit Agricultural Research Center (DZARC) between 17 February 2021 and 5 April 2021. The research station is located 47 km southeast of Addis Ababa and between 80, 44’N latitude and 38, 38’E longitude at an altitude of 1900 m above sea level. The area is known for bimodal rainfall distribution (June–September and March–May), with an average annual rainfall of 814 mm and minimum and maximum temperatures of 10.9 and 28.3°C, respectively (DZARC, 2017). The area is dominated by a mixed crop–livestock farming system with major crops: teff, wheat and chickpea. The map of the study area is indicated in Figure 1.

Figure 1. Map of the study area.

2.2. Experimental diets and preparation

An adequate amount of fresh sugarcane filter cake was procured from Wonji-shoa sugar factory in the Rift-Valley of central Ethiopia and transported to the research station. It was sun-dried by scattering it on a clean concrete floor at 2.5 cm thickness and turning it twice daily for 3 to 4 days until it dried well (>90% DM) (Sahu et al., 2018). The sun-dried SFC was sieved (3 mm) and stored in bags at ambient temperature (Figure 2)

Figure 2. Sieving operation of sun-dried SFC (a) and part of sieved SFC (b).

Samples of the major ingredients used in diet formulation (Table 1) were analyzed for chemical composition using the procedures of AOAC (2010) at the commercial JIJE Analytical Testing Service Laboratory (PLC http://www.jijelaboglassplc.com). The dry matter of the sample was calculated after determining its moisture content: %moisture = [(Initial sample weight—sample weight after drying)/sample weight] x 100%, and %DM = 100 –%moisture. The nitrogen content of the sample was assayed using the Kjeldahl method, and crude protein content (% CP) was estimated as % N x 6.25. Ash was determined by taking dried samples in a muffle furnace heated to a temperature of about 550 until a constant weight was attained. The ash contents of the samples were calculated as:

$\mathrm{A}\mathrm{s}\mathrm{h}\mathrm{\%}\left(\mathrm{D}\mathrm{r}\mathrm{y}\mathrm{b}\mathrm{a}\mathrm{s}\mathrm{e}\right)=\frac{\mathrm{W}\mathrm{e}\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t}\mathrm{o}\mathrm{f}\mathrm{A}\mathrm{s}\mathrm{h}\left(\mathrm{g}\right)}{\mathrm{W}\mathrm{e}\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t}\mathrm{o}\mathrm{f}\mathrm{s}\mathrm{a}\mathrm{m}\mathrm{p}\mathrm{l}\mathrm{e}\left(\mathrm{g}\right)}\times 100$

Table 1. Chemical composition (% DM) and ME (Kcal/kg DM) of major feed ingredients

Ingredients	DM	ME	CP	CF	Fat	Ash	Ca	P
Maize	91.0	3258	9.00	1.70	4.36	1.19	0.04	.30
Wheat middling	91.5	1980	12.91	5.00	3.10	2.42	0.14	.45
Soybean meal	89.5	2180	43.50	7.20	7.40	7.45	0.4	.61
Noug seed cake	90.0	2400	32.63	17.10	7.10	10.01	0.88	1.02
Meat and bone meal	92.0	2830	52.4 0	0	12.00	27.07	7.08	4.51
Sugarcane filter cake	92.5	1105	13.54	18.04	7.05	24.78	4.85	1.7
Soybean oil	99.5	9300	0	0	99.5	0	0	0

DM= Dry matter; CP = crude protein; EE = ether extract; CF= crude fiber; ME = metabolizable energy; Ca = calcium; P = phosphorous. Fresh SFC DM (%) = 35.76

The crude fat contents of the samples were determined by treating them with solvent, using a Soxhlet extractor.

$Crude\hspace{0.17em}fat\mathrm{\%}\hspace{0.17em}=\frac{Weight\hspace{0.17em}of\hspace{0.17em}fat\hspace{0.17em}\left(g\right)}{Weight\hspace{0.17em}of\hspace{0.17em}sample\hspace{0.17em}\left(g\right)}X100$

Crude fiber is measured by boiling the sample in acid and then in alkali. Finally, the ash content of the sample is determined as a loss obtained by burning the residue to ash in a furnace.

$Crudefiber\mathrm{\%}\hspace{0.17em}=\frac{\left(W2\hspace{0.17em}-\hspace{0.17em}W3\right)\left(g\right)}{W1\hspace{0.17em}\left(g\right)}X100$

where W1 is the weight of sample; W2—weight of crucible and dried residue after drying

W3—weight of crucible and residue after incineration

Calcium content of the samples was assayed by the modified AOAC official method (EDTA Titrimetric Method), while phosphorus was by the spectrophotometric method. The fatty acid profiles were determined using gas chromatography–mass spectrometry (GC–MS) method. The ME values of the major feed ingredients were adapted from poultry-based feeding recommendation (PTC⁺ Poultry Production Manual, The Netherlands), while that of SFC (1105 Kcal/kg DM) was its estimated energy value in broiler (Sahu et al., 2016; Suresh & Reddy, 2011).

The experiment was set in three feeding phases: starter (0–14 days), grower (15–28 days) and finisher (29–49 days) (Table 2). A control diet meeting the nutrient requirement of broiler chickens for each growth phase was formulated from conventional feed ingredients (T0). The sugarcane filter cake was included in the control diets at two levels (5% and 10%) and varied in consumption period [(5% (T1) and 10% (T2) for the entire period, 5% (T3) and 10% (T4) for the grower to finisher phase and 5% (T5) and 10% (T6) for finisher phase. The experimental diets were formulated to be iso-nitrogenous and iso-caloric meeting the nutrient requirements for Cobb500 at each phase (Anonymous, 2015). The ingredients were mixed manually and thoroughly and presented in a mash form. The soybean oil portion was blended with the diets daily to avoid its oxidation (rancidity) and feed spoilage upon staying longer after blending.

Table 2. Ingredients and composition (g/kg as fed) of experimental diets

Ingredients	Starter (1–14 days)			Grower (15–28 days)			Finisher (29–49 days)
	SFC0	SFC5	SFC10	SFC0	SFC5	SFC10	SFC0	SFC5	SFC10
Maize	565	560	527	595	600	568	600	600	591.5
Wheat middling	36	17	2	57	12	2	80	25	1
Meat and bone meal	60	60	60	60	47	60	60	60	60
Soybean meal	260	270	263	200	232	213	160	160	184
Noug seed cake	36	5	2	40	12	3	41.5	50	1
Sugarcane filter cake	0	50	100	0	50	100	0	50	100
Soybean oil	20	25	35	29	34	43	41	44	52
Limestone	12	2	1	8	3	1	7	1	1
Salt	4	4	3	4	3	3	4	3.5	3
DL-Lysine	2	2	2	2	2	2	2	2	2
DL-Methionine	2	2	2	2	2	2	1.5	1.5	1.5
Premix*	3	3	3	3	3	3	3	3	3
Nutrient composition (%DM):
Dry matter (%)	90.99	91.03	91.19	91.13	91.15	91.33	91.29	91.31	91.45
Crude protein	21.48	21.29	21.08	19.55	19.48	19.3	18.17	18.41	18.15
Crude fiber	3.67	3.97	4.64	3.42	3.86	4.36	3.28	4.05	4.16
Calcium	1.05	0.91	1.1	0.89	0.84	1.09	0.84	0.87	1.07
Phosphorus	0.67	0.72	0.78	0.65	0.65	0.76	0.64	0.71	0.75
ME (Kcal/kg)	2937	3025	2921	3039	3033	3022	3126	3121	3110

*contains Vit A 1,000,000 IU, Vit D3 200,000 IU, Vit E 10,000 mg, Vit K3 225 mg, Vit B1 125 mg, Vit B2 500 mg, Vit B3 1375 mg, Vit B6 125 mg, Vit B12 1 mg, Niacin 4,000,000 mg, folic acid 100 mg, choline chloride 37,500 mg, antioxidant (BTHT) 0.05%, manganese 0.60%, zinc 0.70%, iron 0.45%, copper 0.05%, sodium 0.01%, selenium 0.004%, calcium 2.7%; ME = metabolizable energy

2.3. Animals and housing

A total of 336 one-day-old unsexed broiler chicks (Cobb500) were purchased from a commercial poultry farm (ALEMA farms, PLC) in Bishoftu town. At the research station, the chicks were weighed (av. 47.56 ± 0.58 g) using a sensitive weighing balance and randomly allotted to seven treatments with three replications 16 chicks/pen) in a Completely Randomized Design.

Chicks were vaccinated for Newcastle disease (NCD) and Gomboro at hatching, followed by the Lasota vaccine (on day 12^th and 24^th) and vitamin administration. Each group of chicks was managed in a deep litter (7-10 cm) pen with concrete floor space 1 m×2.5 m, holding a round feeder and drinker. Infrared bulbs (250 Watts) and fluorescent lamps were used as light sources during the entire feeding period. The ambient temperature of each pen ranged between 28°C and 32°C with relative humidity around 60% during earlier ages and then reduced. The experimental pens were disinfected and sprayed against external parasites before introducing the chicks. The feeders and drinkers were thoroughly cleaned properly, and the standard bio-security measures were implemented at all levels to ensure the health and welfare of the animals. The research was approved for ethical animal experimentation and technical relevance by the Addis Ababa University, College of Veterinary Medicine and Agriculture, which issued an ethical clearance certificate with the reference number VM/ERC/23/06/13/2021.

2.4. Feeding management and measurements

Feed was offered ad libitum to the broilers in each pen daily at 8:00 AM and 2:30 PM. The feed refusal of each pen was collected and weighed the next morning at 08:00 AM, before the new feed was given. Feed intake was determined as the difference between the amount of feed offered and the refusal. Feeds and experimental broilers were weighed using a sensitive weighing balance (CAMRY, Model: ACS-30-JE11, China). The birds in each pen were weighed in a group on day 1 and then weekly. The differences between the two successive weight records were used to compute the average daily weight gains. Feed conversion ratio (FCR) was determined as a ratio of the feed amount consumed to the body weight gain.

At the end of the experimental period, two birds (one male and one female) were randomly selected per pen, starved for 12 h and individually weighed before being slaughtered. After bleeding the birds and manual removal of offal, the carcass parts (breast, drumstick and thighs) were cut up and weighed followed by separation and weighing of the visceral organs (heart, liver, lung and abdominal fat) and gastrointestinal tracts (crop, proventriculus, gizzard, small and large intestine). Dressed carcass weight was measured after the removal of blood, legs, head and feather, and the dressing percentage was computed as the proportion of dressed carcass weight to slaughter weight. Eviscerated carcass percentage was determined as the proportion of eviscerated weight (where the weight of blood, feather, lower leg, head and visceral organs was excluded) to slaughter weight. Of the thigh portion of each carcass, visible fat was carefully removed and lean meat and bone were separated and weighed to determine meat-to-bone ratio (Suresh, 2007). The bones (tibia) that separated from the thigh to proportionate meat and bone were pooled per replication and freed of any adhering soft tissue, including fat in the bone marrow. It was then assayed for total ash, calcium and total phosphorus contents using the procedures of AOAC (2010).

2.5. Partial budget analysis

The partial budget analysis was performed as described by Upton (1979). To estimate the economic benefit of the production, all the variable costs and returns from the sale of live broilers at week 49 were assayed at the prevailing market price.

2.6. Data statistical analysis

Data generated from the experiment (feed intake, body weight gain, feed conversion ratio, carcass parameter and bone composition) were entered into a Microsoft Excel sheet and subjected to one-way ANOVA using SAS (2011, version 9.3). Treatment means were separated using the Tukey test (α, 0.05). Mean contrasts were undertaken between sets of treatments for comparison.

3. Results and discussion

3.1. Nutrient contents of sugarcane filter cake

The chemical analysis of SFC samples used in this study signifies its importance as a source of organic and inorganic nutrients (Tables 1 and 3). Sugarcane filter cake contains moderate levels of crude protein (13%) and is high in minerals, particularly calcium (4.85%) and phosphorus (1.7%). However, it is relatively higher in crude fiber (18%) and total ash (24%) contents which might impair its feed use in poultry. The sugarcane filter cake is also rich in essential (unsaturated) fatty acids such as linoleic and oleic acids as indicated by their higher fractions in the ether extract. The nutrient compositions of SFC are within the range reported in the literature for crude protein (11.76–18.01%), fiber (10.08–17.5%), nitrogen-free extract (37.71–52.08%), calcium (1.2–5.90%) and phosphorous (0.67–1.38%) (Bhosale et al., 2012; Dhas, 2016; Kumar et al., 2015; Sahu et al., 2016; Saleh-E-In et al., 2012; Suma et al., 2007; Suresh & Reddy, 2011). Similarly, our results of SFC fatty acid analysis are close to that of literature reports (%EE) for palmitic acid (30.3–34.18%), stearic acid (4.1%), oleic acid (13.76–17.2%) and linoleic acid (34.85–38.0%) (Sahu et al., 2016; Suresh & Reddy, 2011). The observed variation in the nutrient composition of SFC could be due to differences in sugarcane varieties, farm location and sugarcane processing methods employed at sugar factories.

Table 3. The fatty acids profile of sugarcane filter cake

Fatty acid	Type	Composition
		%DM	%EE
Linoleic acid	Unsaturated	3.01	42.66
Oleic acid	Unsaturated	1.7	24.15
Palmitic acid	Saturated	1.66	23.52
Stearic acid	Saturated	0.16	2.24

EE (% DM) = 7.78

3.2. Feed intake and growth performances

The effect of SFC-based diets on feed intake and growth performances is shown in Table 4. Feed intake at the starter phase was not affected (P > 0.05) by SFC inclusions, but was significantly lower (P < 0.05) during grower and finisher phases in broilers fed 10%SFC diet for the entire period or during the grower to finisher phase. This could be due to the lower adaptation of chickens to a higher level of SFC feeding at early ages. The daily feed intake per bird was significantly reduced (P < 0.05) for 10% than 5% SFC-based diet during the grower phase. The higher crude fiber and fat contents of SFC might have restricted its utilization in broilers since the birds, particularly young chicks, lack enzymes capable of degrading fiber and hydrolyzing fat (Suresh & Reddy, 2011). Regardless of the feeding phase, there were no significant differences (P > 0.05) among the treatments in FI, ADG and FCR; however, intake and weight gains were relatively higher in birds fed 10%SFC-based diet for the entire period. The cumulative (total) feed intake did not significantly differ (P > 0.05) among treatments ranging from 3.86 (T2) to 4.26 kg/bird/49 days (T6). In agreement with our result, Dhas (2016) observed that feed consumption in broiler chickens was not influenced by SFC inclusion with or without using biotechnological agents. Contrarily, Suresh (2007) observed a reduction in weekly and cumulative feed intake of broilers with either 5 or 10%SFC-based diet compared to the control.

Table 4. Feed intake (g/day), body weight gain (g/day), average daily gain (ADG), cumulative feed intake (CFI) and feed conversion ratio (FCR) of cobb500 broilers fed sugarcane filter cake-based diets

Treatment	1–14 days					15–28 days
	FI	IBW	FBW	ADG	FCR	FI	FBW	ADG	FCR
SFC0-control (T0)	33.27	47.83	307.20	18.53	1.75	85.95^a	906.75	42.82^a	2.03^c
SFC5-whole period (T1)	33.14	47.58	301.78	18.16	1.75	85.97^a	854.14	39.45^a	2.20^abc
SFC10-whole period (T2)	33.59	47.70	304.35	18.33	1.75	76.37^b	776.78	33.74^b	2.27^ab
SFC5-grower to finisher (T3)	33.89	47.48	311.94	18.89	1.72	84.82^a	872.10	40.01^a	2.13^abc
SFC10-grower to finisher (T4)	33.22	47.28	303.22	18.28	1.75	79.67^b	790.72	34.82^b	2.33^a
SFC5-finisher (T5)	33.50	48.24	304.80	18.33	1.77	84.93^a	877.14	40.88^a	2.09^bc
SFC10-finisher (T6)	34.91	47.48	317.94	19.32	1.74	86.20^a	906.60	42.04^a	2.06^c
SEM	2.42	0.34	11.16	0.85	0.08	2.37	31.71	1.097	0.04
P-value	0.9990	0.5748	0.9451	0.9646	0.9998	0.0172	0.0580	<.0001	<.0001
Mean contrast:
T1,T2 vs T3,T4	0.9392	0.4562	0.6918	0.6894	0.7886	0.6511	0.6228	0.4573	0.8533
T1,T2 vs T5,T6	0.7291	0.5391	0.4687	0.4988	0.9928	0.0650	0.0303	<.0001	0.0009
T3,T4 vs T5,T6	0.7871	0.1845	0.7389	0.7818	0.7816	0.1628	0.0773	0.0003	0.0017
T1,T3,T5 vs T2,T4 T6	0.8416	0.3360	0.8018	0.7892	0.9963	0.0211	0.1182	0.0003	0.0500
T1,T2,T3,T4,T5,T6 vs T0	0.8677	0.5918	0.9908	0.9786	0.9530	0.2497	0.0991	0.0003	0.0039
Treatment	29–49 days				1–49 days
	FI	FBW	ADG	FCR	FI	CFI	TBWG	ADG	FCR
SFC0-control (T0)	122.04^a	1962.67^cd	50.28^c	2.54^a	86.36	4.23	1914.83^dc	39.08	2.17
SFC5-whole period (T1)	117.34^ab	1998.35^bc	54.48^abc	2.21^abc	84.32	4.13	1950.76^bc	39.81	2.08
SFC10-whole period (T2)	110.40^b	1926.32^cd	54.74^abc	2.18^bc	78.73	3.86	1878.61^dc	38.34	2.08
SFC5-grower to finisher (T3)	114.09^ab	1903.33^cd	49.11^c	2.49^ab	82.81	4.06	1855.85^dc	37.87	2.17
SFC10-grower to finisher (T4)	117.52^ab	1884.93^d	52.10^bc	2.28^abc	82.62	4.05	1837.65^d	37.50	2.14
SFC5-finisher (T5)	119.74^a	2089.13^ab	57.71^ab	2.14^c	85.15	4.17	2040.90^ab	41.65	2.02
SFC10-finisher (T6)	122.28^a	2160.42^a	59.70^a	2.39^abc	87.01	4.26	2112.9^a	43.12	2.11
SEM	2.197	33.76	1.93	0.07	3.17	0.106	33.63	1.53	0.04
P-value	0.0010	0.0004	0.0007	0.0007	0.5897	0.2003	0.0003	0.0882	0.2799
Mean contrast:
T1,T2 vs. T3,T4	0.3791	0.0629	0.0384	0.0157	0.7085	0.5914	0.0629	0.3653	0.1306
T1,T2 vs T5,T6	0.0012	0.0003	0.0343	0.3695	0.1522	0.0538	0.0003	0.0308	0.7176
T3,T4 vs T5,T6	0.0183	<.0001	<.0001	0.1273	0.2899	0.1421	<.0001	0.0022	0.0611
T1,T3,T5 vs T2,T4 T6	0.8564	0.8202	0.2678	0.9935	0.6142	0.4711	0.8273	0.9207	0.5546
T1,T2,T3,T4,T5,T6 vs T0	0.0308	0.4083	0.0370	0.0025	0.3947	0.2315	0.4036	0.6995	0.1952

Means within column and within main effect not sharing a common superscript letter differ significantly (P < 0.05); SFC= sugarcane filter cake; FI = feed intake, IBW= initial body weight; FBW= final body weight; ADG= average body weight gain; FCR= feed conversion ratio; CFI = cumulative feed intake (kg/bird/49 days); TBWG= total body weight gain

The average daily gain (ADG) of broilers was lowered (P < 0.05) at the grower phase on 10%SFC-based diet beginning from the starter or grower phase. At the finisher phase, the ADG of the broilers was significantly higher (P < 0.05) with 5% and 10% SFC-based diets when compared to the control. However, the overall ADG was not significantly different (P > 0.05) among the treatments. The total body weight gain (TBWG) peaked in broilers fed 5 and 10%SFC diets only at the finisher phase (P < 0.05). The trend in weekly weight has shown a slight variation between weeks 3 and 7, where better final live weights were attained by 5 and 10%SFC diets fed at the finisher phase alone (Figure 3). This could be due to the birds’ gut morphological development at later ages that might have favored fibrous feed utilization and performances. Contrarily, Suresh (2007) observed a significantly reduced TBWG (from 1999.7 to 1803.8 g/bird) at the finisher phase in broiler fed 10% SFC diets for the entire period.

Figure 3. Trend of weekly average body weight of experimental animals.

Feed conversion ratio (FCR) was not affected (P > 0.05) by SFC inclusions at the starter phase but varied (P < 0.05) during grower and finisher phases where a 5% SFC diet for the entire period or a 10%SFC diet at finisher phase alone are comparable with control. Feed conversion ratio (FCR) was lower (P < 0.05) by allowing 5%SFC-based diet only at the finisher phase compared to at the grower to finisher phase (T3) or the control (T0). On the other hand, the broilers maintained on 10%SFC-based diet (T2) for the entire period had better FCR at finisher phase than at grower phase. In agreement with our results, Suresh (2007) reported a significantly reduced FCR in broilers fed 10%SFC diet for the entire period, varying with control group at the starter phase (1.66 vs. 1.57), finisher phase (2.20 vs. 1.94) and cumulatively (1.91 vs. 1.77). However, the overall FCR was not influenced (P < 0.05) by dietary treatments in the present study.

In agreement with the present results, various studies have reported the positive role of agricultural waste products supplementation on poultry performance and health, production cost and product quality, replacing the conventional feed ingredients in the diet (Abo Ghanima et al., 2020; Bonos et al., 2022; Seidavi et al., 2021). According to Bonos et al. (2022), a 10% silage-based diet (where the silage was made from a mixture of olive mill wastewater, grape pomace and deproteinized feta cheese whey) had significantly increased body weight gain, feed intake and FCR in broiler chickens. Beriso et al. (2022) examined the effect of boiled mango seed kernel at 0, 5, 10 and 15% replacement for maize in diets for broiler chickens and found a remarkable growth performance, feed intake, FCR and economic benefit at lower inclusion level, while significantly reduced at higher levels. A review work by Seidavi et al. (2020) has shown the potential of citrus by-products in poultry feed formulation, replacing maize and improving chicken performances and health and product quality. Calla et al. (2021), used rice bran as a feed ingredient at levels 0, 5, 10, 15, 20 and 25% in broiler diets and reported that up to 20% inclusion had a positive effect on growth performance, carcass yield and sensory traits and reduced cost of production.

3.3. Carcass yield and quality

Table 5 summarizes the effect of SFC inclusion in the diet on carcass characteristics of broilers. There was no variation (P > 0.05) in carcass parameters among the broilers due to SFC inclusion and its phase feeding. Dressing percentage (DP, dressed weight as part of live weight) ranged from 85.56 (T1) to 89.79 (T4), while as part of eviscerated carcass weight (EP) ranged from 62.18% (T1) to 65.40% (T3). In agreement with our result, there was no difference in DP between the control diet and 5% (78.44) and 10% (76.86) SFC-based diets (Suresh et al., 2009). In the present study, the weight (g/bird) of breast meat, thigh and drumstick ranged from 556.6 (T2) to 667.5(T6), 209.2 (T1) to 234.2 (T0) and 193.3 (T2) to 217.3 (T6), respectively. Of the visceral organs, the weight of the gizzard was numerically increased from 26.68 (T0) to 32.17 g (T6) due to SFC inclusion. However, there was no variation (P > 0.05) in abdominal fat weight among the treatments, as opposed to Suresh et al. (2009), who reported a lower abdominal fat weight of Hubbard chickens on 10%SFC based diet when compared to control group (27.79 versus 19.13 g). The meat-to-bone ratio was higher (P < 0.05) in broilers fed 10%SFC diets during grower to finisher phase (5.40) than in the group fed at finisher phase (4.07). In addition, the meat-to-bone ratio did not differ between the control and the group on either 5 or 10%SFC-based diets for the entire period, which is in accordance with Suresh et al. (2009).

Table 5. Yield of carcass and non-carcass components (g/bird, except SBW,kg) of broilers (n = 6) slaughtered at 49 days of age

Treatment	SBW	DP	EP	Breast	Thigh	Drum- stick	Back	Wing	Gizzard	Heart	Liver	Crop	Pro	SI	LI	Abd Fat	MB ratio
SFC0-control (T0)	2.20	87.84	64.58	665.83	234.17	201.67	187^ab	86.17	26.68	11.10	33.73	5.48	8.63	49.65	7.20	29.35	4.43^ab
SFC5-whole period (T1)	2.08	85.57	62.18	573.33	209.17	205.00	164.2^bc	79.17	29.46	9.02	33.83	7.70	7.70	57.95	8.35	29.07	4.50^ab
SFC10-whole period (T2)	2.10	87.05	65.00	556.67	225.00	193.33	191.7^a	85.00	31.28	9.25	29.65	5.92	7.32	61.40	7.52	29.35	4.50^ab
SFC5-grower to finisher (T3)	2.13	86.32	65.40	606.67	231.83	202.5	160.2^c	87.00	27.40	9.07	33.42	5.52	9.42	59.47	7.93	30.75	4.77^ab
SFC10-grower to finisher (T4)	2.21	87.89	63.24	632.5	233.33	206.66	186.7^ab	87.50	31.13	10.98	33.78	6.35	7.47	50.92	7.75	30.48	5.40^a
SFC5-finisher (T5)	2.15	87.45	65.34	595.83	220.83	208.33	186.7^ab	83.33	30.82	8.91	33.58	6.70	7.73	56.60	9.45	29.48	4.67^ab
SFC10-finisher (T6)	2.30	86.54	64.51	677.50	231.67	217.33	185^ab	87.50	32.17	10.75	34.67	6.10	7.48	62.47	10.20	29.67	4.07^b
SEM	0.09	.69	1.26	45.21	14.13	12.25	7.60	3.90	1.88	0.89	2.84	.68	.66	4.43	1.09	0.58	0.26
P-value	0.683	.209	.514	0.436	0.865	0.902	0.027	0.730	0.313	0.288	0.917	.301	.249	0.304	0.441	0.329	0.032
Mean contrast:
T1,T2 vs. T3,T4	0.402	.257	.571	0.235	0.280	0.661	0.556	0.194	0.559	0.326	0.518	.212	.164	0.318	0.934	0.020	0.028
T1,T2 vs T5,T6	0.166	.331	.300	0.122	0.521	0.272	0.303	0.399	0.557	0.439	0.408	.557	.880	0.975	0.093	0.530	0.616
T3,T4 vs T5,T6	0.574	.870	.634	0.708	0.657	0.505	0.110	0.642	0.245	0.832	0.855	.502	.213	0.333	0.079	0.080	0.007
T1,T3,T5 vs T2,T4 T6	0.280	.214	.958	0.418	0.421	0.960	0.008	0.280	0.143	0.078	0.697	.364	.117	0.944	0.921	0.888	0.956
T1,T2,T3,T4,T5,T6vsT0	0.632	.212	.827	0.237	0.565	0.772	0.338	0.769	0.078	0.146	0.852	.235	.279	0.085	0.267	0.475	0.449

SBW= slaughter body weight, DP= dressing %, EP= eviscerated %, Pro= proventriculus, SEM= standard error of means, SI= small intestine, LI=large intestine,

Abd fat=abdominal fat, MB ratio=meat to bone ratio, SFC₅= 5% filter cake, SFC₁₀= 10% filter cake, T= treatment

3.4. Bone (tibia) mineralization

The mineral composition of the tibia and the ratio of calcium to phosphorus were significantly different (P < 0.05) among the treatments (Table 6). Tibia had higher ash and calcium composition in broilers-fed SFC-based diet for the entire period or from grower to finisher phase compared to the group fed SFC diets only at the finisher phase. However, there were no differences (P > 0.05) in tibia ash, calcium and phosphorus contents between 5% and 10%SFC diets and between SFC-based diets from starter to finisher phases and control diet. Although statistically not significant (P > 0.05), most of the mineral contents of the tibia were numerically increased with SFC inclusion in the diet when compared to that of the control diet. The ratio of calcium to phosphorus in the tibia was significantly decreased (P < 0.05) with phase feeding from 2.44 (T2) to 1.87 (T4), indicating SFC inclusion in the diet for the entire period improves calcium absorption in broilers. The present tibia mineralization with SFC inclusion further indicated the bioavailability of calcium and phosphorus contained in SFC. The present findings were in accordance with Dhas (2016) and Suresh (2007) who reported that tibia mineralization was not impaired by SFC inclusion in broiler diets for the entire period. Moreover, Suresh (2007) observed a significantly higher calcium content of tibia bone in broilers (Hubbard) fed up to 10%SFC-based diets, but insignificantly for phosphorus content. In general, past and present studies revealed that bone mineralization is favored with SFC inclusion in the diet of broilers.

Table 6. Least square means of tibia ash, calcium and phosphorus composition of broilers (49 d) fed diets-based sugarcane filter cake

Treatment	%DM tibia
	Total ash	Calcium	Phosphorus	Ca : P ratio
SFC0-control (T0)	48.81^ab	19.83^a	8.62^ab	2.29^a
SFC5-whole period (T1)	52.10^a	19.28^a	8.90^a	2.18^ab
SFC10-whole period (T2)	52.03^a	20.10^a	8.23^b	2.44^a
SFC5-grower to finisher (T3)	51.31^ab	18.29^ab	8.91^a	2.05^b
SFC10-grower to finisher (T4)	51.57^ab	17.08^ab	9.15^a	1.87^b
SFC5-finisher (T5)	46.76^b	15.10^b	8.00^b	1.89^b
SFC10-finisher (T6)	47.52^b	15.98^b	8.10^b	1.97^b
SEM	1.05	1.06	0.25	0.121
P-value	0.0089	0.0277	0.0376	0.0342
Treatment contrast:
T1,T2 vs. T3,T4	0.5646	0.0785	0.0878	0.0111
T1,T2 vs T5,T6	0.0004	0.0015	0.0663	0.0068
T3,T4 vs T5,T6	0.0012	0.0621	0.0019	0.8093
T1,T3,T5 vs T2,T4 T6	0.7190	0.8508	0.6071	0.5908
T1,T2,T3,T4,T5,T6 vs T0	0.2385	0.0755	0.7994	0.1069

^a,bMeans within a column lacking a common superscript differ (P < 0.05).

3.5. Mortality

Although losses are insignificant, mortality of broiler chickens was noted during experimental period. Only 4 birds suddenly died at earlier ages, and 10 birds were culled, irrespective of the treatment effect, due to severe leg weakness during the finisher phase. The mortality rate of broilers was computed to be 4.1% (proportion of lost birds to total birds). Apart from the birds culled or found dead, no other health problem was observed due to the test diet effect, or improper management practices including bio-security measures. The sudden death could probably be due to acute heart failure. The current mortality is medium compared to 7.8% mortality reported for cobb500 for the on-farm study (Dessie et al., 2017) and 1% for the on-station study (Habtie et al., 2021).

3.6. Economic analysis

The results of the partial budget analysis are indicated in Table 7. The feed cost of production was slightly decreased from 75.4 (T0) to 69.14 birr/bird (T2) due to SFC inclusion in the diet. However, the feed cost and total variable cost of broiler chickens fed 10%SFC diet only at the finisher phase surpassed that of the control diet by about a unit price. Using the then market price of broilers based on live weight, the total revenue per bird in T1, T5 and T6 exceeded that of the control group. However, the net income was increased over control by feeding SFC-based diet for the whole period or only at the finisher phase, which was also confirmed by the positive change in net income or by increased benefit-to-cost ratios. The highest MRR (25.6) was obtained with 10%SFC-based diet fed only at the finisher phase. Based on the present study, broiler production is economically more beneficial when raised on SFC-based diets at the finisher phase, resulting in 19 to 24 birr/bird increment over that of the control group. This revealed that 5 and 10 % SFC inclusion in the diet for the entire feeding period or at the finisher phase alone had led to increased profit due to the consumption of less costly feed and increased final body weight of broilers. Conversely, a study by Suresh et al. (2012) found that a diet with 10%SFC fed to chickens had significantly lower net profit per bird compared to the control group. They concluded that including SFC beyond 5% is not cost-effective.

Table 7. Result of partial budget analysis of broiler chickens reared on SFC-based diets (1–49 days; in birr/bird)

Parameter	Treatments
	SFC0-control (T0)	SFC5-whole period (T1)	SFC10-whole period (T2)	SFC5-grower to finisher (T3)	SFC10-grower to finisher (T4)	SFC5-finisher (T5)	SFC10-finisher (T6)
Chick purchase	30	30	30	30	30	30	30
Medication cost	7	7	7	7	7	7	7
Labor cost	21.87	21.87	21.87	21.87	21.87	21.87	21.87
Feed cost	75.4	72.96	69.14	72.06	72.70	73.88	76.34
TVC cost	134.27	131.83	128.01	130.92	132.74	131.56	135.21
Total return(TR)	245	250	241.25	237.5	235	261.25	270
Net income	110.73	118.17	113.24	106.58	102.26	129.69	134.79
cNI	0	7.44	2.51	−4.15	−8.47	18.96	24.06
cTVC	0	−2.44	−6.26	−3.35	−1.53	−2.71	0.94
MRR(cNI/cTVC)	-	3.05	0.40	na	na	6.99	25.60
TR:TVC ratio	1.82	1.90	1.88	1.81	1.77	1.99	2.00

TVC: total variable cost, cNI: change in net income, cTVC: change in total variable cost, MRR: marginal ret of return; na = not applicable; purchase price of day old chicks = 30 birr/head; sell price of finished broilers = 125 birr/kg body weight

4. Conclusion and recommendations

Results of this study have shown that SFC-based diets (5% and 10% SFC) had no adverse effect on feed consumption and growth performances of broiler chicks during the starter phase. However, the higher inclusion rate (10%SFC) beginning from the starter or grower phase reduced the subsequent growth. The SFC-based diet fed only at the finisher phase resulted in better feed intake and body weight gain than the other groups. Carcass yields were not affected by the inclusion of SFC in the diet. Better revenue and net income were obtained from the broilers fed on SFC-based diets only at the finisher phase. In conclusion, SFC is a potential alternate feed ingredient for broilers as its part in the diet up to 10% for the entire feeding period or at the finisher phase improves both biological and economic performances.

The present study has revealed the need for further studies to exploit the potential feed use of SFC in the poultry industry. We, therefore, recommend in-depth studies on the following aspects:

• To determine the effect of a higher dietary inclusion of SFC on broiler performances, blood biochemical composition and meat chemical composition and fatty acid profiles.

• To investigate the best SFC processing option to reduce fiber and total ash fractions and improve its utilization in the diet.

4.1. The strengths and limitations of the study

This study has proved that sugarcane filter cake is considerably used as an alternative nutrient-rich ingredient for broiler feed production, showing remarkable performances. However, a major limitation of the study was the lack of information on blood serum cholesterol, total protein, glucose, calcium and phosphorus concentration, supporting animal performance findings.

Correction

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Acknowledgments

The authors would thank the Ethiopian Institute of Agricultural Research (EIAR) and also thanks poultry research assistants for their unreserved role to implement the experiment.

Disclosure statement

No conflict of interest was reported by the authors.

Additional information

Funding

The research was funded by Ethiopian Institute of Agricultural Research

Notes on contributors

Mariye Melkam

Mariye Melkam is an associate researcher at Debre Markos Agricultural Research Center, Ethiopian Institute of Agricultural Research. Her main research focus is on poultry nutrition.

Getahun Kebede

Getahun Kebede is a senior researcher at Debre Zeit Agricultural Research Center, Ethiopian Institute of Agricultural Research. His main research focus is on ruminant and non-ruminant nutrition.

Ashenafi Mengistu

Ashenafi Mengistu is a lecturer and an Associate professor at College of Veterinary Medicine and Agriculture, Addis Ababa University. His main interest is on ruminant and non-ruminant nutrition.