Influence of high-oil algae biomass as a feed intake and growth-performance enhancer in feedlot cattle during period of high ambient temperature

Abstract

Sixty calf-fed Holstein steers (290 ± 2 kg) were used in a 90-d trial to evaluate the influence of fresh high-oil algae biomass as a feed intake and growth-performance enhancer in feedlot cattle. Steers were grouped into 5 weight blocks, and randomly assigned within blocks to 15 pens (4 steers per pen, 4 pens per treatment). All steers were fed the same steam-flaked corn-based basal growing-finishing diet. Three treatments were evaluated (1) basal diet, (2) basal diet plus 60 g/head water or (3) basal diet plus 60 g/head high-oil algae biomass. On an as-fed basis, the algae biomass contained: 78.4% moisture, 2.15% ash, 0.21% N, 0.07% starch, 0.50% neutral detergent fiber and 17.2% ether extract. Steers were fed once daily. Water and algae biomass treatments were top-dressed onto the basal diet at time of feeding. On a dry matter basis, algae biomass application accounted for 0.14% of average daily feed intake. Top-dressing the basal diet with water did not affect (P > 0.20) cattle growth performance or dietary net energy (NE). In contrast, top-dressing feed with algae biomass increased average daily gain (7.8%, P = 0.02), and tended to increase gain efficiency (5.7%, P = 0.08) and estimated dietary NE (3.7%, P = 0.09). We conclude that application of low levels of high-oil algae biomass may enhance daily weight gain of feedlot cattle during period of high ambient temperature. This effect is due in part to an apparent increase in efficiency utilization and in part to an increased dry matter intake.

Keywords:

• algae
• cattle
• performance
• feedlot

1. Introduction

Summer heat load causes a reduction in feed and energy intakes (Young & Hall 1993; Hahn 1994); and subsequently in animal productivity (Blackshaw & Blackshaw 1994). In cattle, this can result in decreased growth rate and gain efficiency (Turner 1984; Hubbard et al. 1999). Algae contain chemical compounds that serve as attractants to augment feed consumption in aquatic species (Mustafa et al. 1997; Tierney and Atema 1998; Jaime-Ceballos et al. 2007). The objective of this study is to evaluate the influence of top-dressing a steam-flaked corn-based growing-finishing diet with a low level (0.14%) of high-oil algae biomass as an agent to enhance energy intake during a period of high ambient temperature.

2. Materials and methods

All procedures involving animal care and management were in accordance with and approved by the University of California, Davis, Animal Use and Care Committee.

2.1. Animals and diets

Sixty calf-fed Holstein steers (290 ± 2 kg) were used in a 90-d experiment to evaluate the influence of algae as a feed intake and growth-performance enhancer in feedlot cattle with respect to feedlot growth performance and dietary NE. This trial was conducted during months of May through July at the University of California Desert Research Center located in El Centro, CA. The average climatic conditions during this experiment were: air temperature 31.0°C (range 28.0–34.0°C), relative humidity 45%. Temperature-humidity index (THI) was calculated using the formula: THI = [0.8 × ambient temperature] + [(% of relative humidity/100) × (ambient temperature – 14.4)] + 46.4 (Mader et al. 2006). Accordingly, the mean THI value during the course of this study was 78.8. In accordance with THI code (Normal THI < 74; Alert 75 < THI < 78; Danger 79 < TH I < 83; and Emergency THI > 84), steers in the trial were exposed to ‘danger’ situation due hot environmental conditions. Eight days before initiation of the study, steers were individually weighed, implanted with Revalor-S (Intervet Inc., Millsboro, DE), grouped by weight into 5 blocks, and randomly assigned within weight blocks to 15 pens (4 steers per pen). Pens were 75 m² with 27 m² of overhead shade, automatic waterers, and 4.3 m fence-line feed bunks. All steers were fed the same basal diet (sudangrass hay: 6.00%, yellow grease: 2.50%, molasses cane: 5.00%, urea: 0.50%, limestone: 1.65%, magnesium oxide: 0.05%, trace mineral salt: 0.30%. Nutrient composition (DM basis) NE_m: 2.21 Mcal/kg, NE_g 1.54 Mcal/kg, CP: 14%, Fat: 6.9%, ash: 6.2%, Ca: 0.81%, Mg: 0.27%, P: 0.44%, K: 0.97, S: 0.19%). Three treatments were evaluated (1) basal diet, (2) basal diet top-dressed with 60 g/head water or (3) basal diet top-dressed with 60 g/head high-oil algae biomass (LFS™, SunEco Energy, Chino, CA). The algae biomass used in this study was derived from a cultivate of naturally occurring colonies of algae, consisting of over 30 species of predominately green and blue-green algae. The algae biomass contained (DM basis): 1.9% ash, 2.1% CP and 13.8% ether extract (0.02% Caprylic, 0.05% Lauric, 0.32% Myristic, 14.15% Palmitic, 0.26% Palmitoleic, 0.09% Margaric, 0.06% Margaroleic, 2.59% Stearic, 31.22% Oleic, 48.16% Linoleic, 1.89% Linolenic, 0.41% Arachidic, 0.44% Eicosenoic, 0.16% Behenic, 0.16% Lignoceric and 0.02 % other fatty acids ). Steers were fed once daily. Water and algae biomass treatments were applied to the basal diet at time of feeding. On a dry matter basis, algae biomass application accounted for 0.14% of average daily feed intake. Steers were allowed ad libitum access to feed. Fresh feed was provided once daily in the morning feeding.

2.2. Estimation of dietary NE

Energy gain (EG) was calculated by the equation: EG = ADG^1.097 0.0557 W^0.75, where EG is the daily energy deposited (Mcal/d), W is the mean shrunk weight (kg; NRC 1984). Maintenance energy (EM) was calculated by the equation: EM = 0.084 W^0.75 (NRC 1988). Dietary NEg was derived from NEm by the equation: NEg = 0.883 NEm – 0.42 (derived from NRC 1996; R² = 0.9997). Dry matter intake is related to energy requirements and dietary NEm according to the equation: DMI = EG/(0.883 NEm – 0.42), and can be resolved for estimation of dietary NE by means of the quadratic formula: x = (–b ± (b² – 4ac)^0.5)/2c, where x = NEm, a = –0.42 EM, b = 0.883 EM + 0.42 DMI + EG, and c = –0.883 DMI (Zinn & Shen 1998).

2.3. Statistical design and analysis

For calculating steer performance, initial and final weight were reduced 4% to account for digestive tract fill. Pens were used as experimental units. The experimental data were analysed as a randomized block design experiment. Treatments effects were tested by means of orthogonal contrasts (Hicks 1973). Analysis performed using Statistix^®8 (Analytical Software, Tallahassee, FL).

3. Results and discussion

Treatment effects on growth performance and estimated NE value of the diet are shown in Table 1. As expected, top-dressing the basal diet with water did not affect cattle growth performance or dietary NE. In contrast, top-dressing feed with algae biomass increased average daily gain (ADG) (7.8%, P = 0.02), and tended to increase gain efficiency (5.7%, P = 0.08) and estimated dietary NE (3.7%, P = 0.09). Of the improvement in ADG, 56% is attributable enhanced efficiency of energy utilization (increased estimated dietary NEm and NEg), and 44% to DMI.

Table 1. Treatment effects on 90-d feedlot growth performance and dietary NE of Holstein steers.

	Treatments			P value
Item	None	Top-dress Water	Top-dress Algae	None vs. Water	Water vs. Algae	SEM
Pen replications	5	5	5
Body weight^a, kg
Initial	289	291	292			2
Final	440	439	453	0.79	0.02	3
ADG, kg/d	1.68	1.64	1.79	0.51	0.02	0.04
DMI, kg/d	8.59	8.48	8.77	0.61	0.20	0.14
ADG/DMI	0.195	0.194	0.205	0.78	0.08	0.004
Dietary NE, Mcal/kg
Maintenance	2.216	2.214	2.295	0.97	0.09	0.030
Gain	1.533	1.532	1.602	0.97	0.09	0.027
Observed/expected NE
Maintenance	1.021	1.020	1.057	0.97	0.09	0.014
Gain	1.027	1.026	1.073	0.97	0.09	0.018

^a Initial and final live weights reduced 4% to account for fill.

The effects of feeding high-oil algae biomass to feedlot cattle has not been investigated previously. Algae have been shown to contain chemicals attractants (Mustafa et al. 1997; Jaime-Ceballos et al. 2007) that promote feed intake in aquatic species (Tierney & Atema 1988). The fresh algae biomass material used in the present study exhibits a very strong ‘algae’ odour, to which anecdotally, we observed that cattle demonstrated a surprisingly strong preference. Accordingly, we conducted this trial under the notion that in a manner comparable to that observed in aquatic species, fresh algae biomass might likewise act to enhance feed intake and hence, ADG of feedlot cattle. However, although DMI was numerically greater in cattle fed the basal diet top-dressed with algae biomass, the marked increase in ADG was largely due to an apparent increased efficiency of energy utilization. The basis for this effect is not certain. In a 35-d feeding trial, supplementation with low levels of dried ground spirulina 0.1g/kg body weight) improved ADG, DMI and gain efficiency of fattening lambs (El-Sabagh et al. 2014). Authors hypothesized that this effect was due to enhanced antioxidant and immune stimulation (increased total white cell count and serum globulin, and increased ratio of reduced glutathione). In contrast, in a 211-d feeding trial, supplementation of feedlot cattle with dried ground spirulina (0.1% of dry matter intake) did not affect growth performance or dietary NE (Zinn & Shen 1996).

This study did not address any potential effects of algae biomass supplementation on meat flavour. High levels of marine algae oil supplementation of milk replacer (12% of milk replacer dry matter as docosahexaenoic acid) for pre-ruminant kid goats resulted in an off flavour in the meat (Moreno-Indias et al. 2012). However, when supplemented at 6% of milk replacer dry matter, no appreciable effects on meat sensory properties were detected. In the present study, algae oil accounted for 0.02% of dry matter intake.

4. Implications

Application of low levels of high-oil algae biomass may enhance daily weight gain of feedlot cattle during period of high ambient temperature. This effect is due in part to an apparent increase in efficiency of energy utilization and in part to an increased dry matter intake. More work is needed to better understand the role of algae in these processes.