Effect of Dietary Restriction and Hay Inclusion in the Diet of Slow-Growing Broilers

Figures & data

Table 1. Ingredients and nutrient composition of experimental diets.

	Phases
	21 to 49 d	50 to 70 d
Ingredients, %
Corn	66.26	69.94
Soybean meal 45%	28.43	24.85
Soybean oil	1.99	2.40
Limestone	0.89	0.79
Dicalcium phosphate	1.14	0.88
NaCl	0.400	0.400
DL-Methionine 99%	0.226	0.170
L-Lysine HCl 78.5%	0.194	0.154
L-Threonine 98%	0.030	0.010
Premix vitamins and minerals^°^#	0.400	0.400
BHT	0.010	0.010
Total	100.00	100.00
Calculated composition
Crude protein, %	18.40	17.00
Metabolisable energy, kcal/kg	3075	3150
Calcium, %	0.70	0.58
Available phosphorus, %	0.31	0.26
Digestible Met+Cys, %	0.74	0.65
Digestible Lys, %	1.01	0.89
Digestible Thr, %	0.66	0.58
Digestible Trp, %	0.20	0.18

BHT, butylated hydroxytoluene.

°Vitamin mixture (content per kg of diet): vitamin A (retinyl acetate), 2250 U; vitamin D₃ (cholecalciferol), 450 U; vitamin E (DL-α-tocopheryl acetate), 7000 U; vitamin K₃ (menadione dimethylpyrimidinol), 418 U; vitamin B1 (thiamine mononitrate), 300 mg; vitamin B₁₂ (cyanocobalamin), 2300 µg; niacin (niacinamide), 7000 mg; calcium pantothenate, 2500 mg; folic acid, 140 mg; D-biotin, 14 mg.

#Mineral mix (content per kg of diet): Fe (iron sulfate monohydrate), 12.5 g; Cu (copper sulfate pentahydrate), 3000 mg; I (calcium iodate), 250 mg; Zn (zinc oxide), 12.5 g; Mn (manganous oxide), 15 mg; Se (sodium selenite), 75 mg; Co (cobalt sulfate), 50 mg.

Table 2. Performance, litter moisture, organ weights, intestine length and pH of contents from gizzard and caecum (mean±standard error) of slow-growing broilers at 70 days of age, under feed restriction and hay inclusion diets.

	Treatments				CV, %
	Control	80% control	80% control+alfalfa	80% control+coast cross
Weight gain, g	2440.25±7.60^a	2180.00±20.68^b	2025.00±30.37^c	2065.75±14.17^c	1.84
Feed intake, g	6734.25±82.52^a	5413.00±00.00^c	6470.50±48.45^b	6365.00±34.24^b	1.63
Feed to gain ratio^°, g/g	2.760±0.05^b	2.483±0.05^c	3.196±0.06^a	3.081±0.06^a	3.67
Litter moisture, %	21.62±1.21	20.55±0.41	21.46±0.86	21.63±0.66	7.85
Proventriculus, %	0.37±0.02^a^b	0.30±0.01^b	0.43±0.02^a	0.41±0.02^a	12.96
Gizzard, %	2.08±0.03^b	1.89±0.03^b	2.84±0.18^a	2.78±0.11^a	9.14
Small intestine, %	3.14±0.09^b	2.73±0.05^c	3.53±0.06^a	3.62±0.13^a	5.13
Large intestine, %	0.48±0.05^b	0.47±0.03^b	0.70±0.02^a	0.68±0.03^a	11.99
Small intestine, cm	195.63±3.52^a	170.88±2.51^b	196.25±6.40^a	194.38±4.77^a	4.80
Large intestine, cm	45.91±1.55^a^b	42.07±2.24^b	49.84±1.40^a	48.99±1.00^a	6.90
pH gizzard	2.66±0.17	2.61±0.13	2.70±0.07	2.53±0.08	8.98
pH caecum	6.60±0.04	6.85±0.05	6.68±0.20	6.83±0.10	3.45

CV, coefficient of variation.

^a-cMeans followed by different letters in same row differ significantly by Tukey’s test (P<0.05).

°Values corrected for mortality.

Table 3. Intestinal morphometry and goblet cells (mean±standard error) from segments of small intestine and caecum of slow-growing broilers at 70 days of age, under feed restriction and hay inclusion diets.

Segments	Treatments				CV, %
	Control	80% control	80% control+alfalfa	80% control+coast cross
Villus height, µm
Duodenum	1524.98±28.37^b	1357.83±52.07^c	1662.45±25.08^a	1657.65±17.09^a	25.26
Jejunum	1001.36±46.24	967.45±58.47	944.54±19.08	1058.66±48.05	7.91
Ileum	677.59±89.22	539.21±30.63	650.17±37.23	691.78±49.10	22.08
Cecum	201.67±3.26^a	193.82±3.64^a	217.77±3.04^b	214.49±2.29^b	14.94
Villus width, µm
Duodenum	125.71±13.76	127.81±1.59	120.80±7.20	117.43±5.50	11.66
Jejunum	124.14±4.82	145.95±24.72	105.38±7.49	112.89±7.49	19.87
Ileum	151.28±9.91	168.75±13.60	151.98±5.49	129.40±21.18	18.72
Crypt dept, µm
Duodenum	117.43±7.74^b	107.44±2.51^b	155.39±2.54^a	173.40±8.06^a	26.56
Jejunum	128.18±5.55^b^c	114.42±7.26^c	143.26±2.55^a^b	167.50±8.00^a	28.11
Ileum	117.83±12.69	87.87±5.48	115.24±5.05	110.63±11.16	17.19
Cecum	104.14±5.58^a^b	93.65±5.34^b	113.14±3.69^a	113.62±2.15^a	8.47
Villous:crypt ratio
Duodenum	14.32±0.93^a	13.86±0.52^a	11.20±0.22^b	10.27±0.29^b	7.88
Jejunum	8.37±0.47^a	8.98±0.11^a	6.93±0.13^b	6.42±0.32^b	6.71
Ileum	8.02±1.04	4.81±0.32	6.04±0.63	6.55±0.54	22.40
Cecum	2.11±0.05	2.09±0.10	1.93±0.08	1.91±0.02	6.95
Goblet cells, cm² of villi
Duodenum	359.75±23.57	298.25±67.81	371.50±28.36	364.25±34.73	24.29
Jejunum	780.50±30.16	439.00±31.46	517.75±9.92	520.00±24.80	10.50
Ileum	508.00±31.95^b	473.25±50.55^b	699.75±40.27^a	683.25±25.29^a	12.93

CV, coefficient of variation.

^a-cMeans followed by different letters in same row differ significantly by Tukey’s test (P<0.05).

Table 4. Economic analysis of feeding programmes using feed restriction and hay supplementation of slow-growing broilers from 21 to 70 days of age.

	Treatments
	Control	80% control	80% control+alfalfa	80% control+coast cross
Feed cost, US$	2.90	2.33	2.74	2.67
ACF, US$/kg	1.19	1.07	1.35	1.29
AGR, US$	4.60	4.11	3.82	3.90
GM, US$	1.71	1.78	1.08	1.23
PI, %	0.59	0.76	0.39	0.46
BP, kg	1.54	1.23	1.45	1.41

ACF, average cost of feed; AGR, average gross revenue; GM, gross margin; PI, profitability index; BP, balance point.