Glutamate Supplementation Improves Growth Performance, Rumen Fermentation, and Serum Metabolites in Heat-Stressed Hu Sheep

Abstract

This study evaluated the effect of glutamate supplementation on the physiological parameters of heat-stressed Hu sheep. Forty-eight male Hu sheep with an average initial body weight of 17.74 ± 0.17 kg were randomly divided into two groups: The control group (CON) was fed a basal diet and a treatment group (GLU) was fed a basal diet + 3 g/head/day of L-glutamate. There were six replications in each group with four sheep in each replication for a 90 days feeding test. Growth performance, serum biochemistry, and serum hormones were measured during phase 1 (1–30 days), phase 2 (31–60 days), and phase 3 (61–90 days) of the experiment; rumen fermentation characteristics, nutrient digestibility, and slaughter performance were measured at the end of the experimental periods. There were no differences in growth performance, serum biochemical indices, and immune indices between CON and GLU during phases 1 and 2. However, a higher average daily gain (ADG), a lower average daily feed intake (ADFI), and a lower F:G ratio (ADFI/ADG) were observed in GLU during phase 3 (p < 0.05). Serum levels of glutamate, globulin, immunoglobulin A, immunoglobulin G, immunoglobulin M, and growth hormone in GLU were higher than those in CON only on day 90 (p < 0.05). Serum levels of heat shock protein 70, adrenocorticotrophic hormone, corticosterone, triiodothyronine, and tetraiodothyronine in GLU were lower than those in CON on day 90 (p < 0.05). At the end of the experiment, ruminal pH, microbial crude protein, ammonia nitrogen, and isovalerate concentrations in GLU were higher than those in CON (p < 0.05). The apparent digestibility of dry matter, organic matter, and crude protein in GLU was higher than those in CON (p < 0.05). There were no differences in carcass traits and organ indices but spleen weight and spleen index tended to be higher in GLU. In conclusion, dietary glutamate supplementation improved rumen fermentation, increased nutrition digestibility and metabolism, enhanced immunity, and promoted growth performance of heat-stressed Hu sheep. This suggests that a longer period of glutamate supplementation (not less than 60 days) at a level of 3 g/head/day is beneficial to Hu sheep under heat stress.

Biochemical and protein nutritional potential of mulberry (Morus alba L.) leaf: partial substitution improves the nutrition of conventional protein

“…The proteins of Sample 13 had the highest total amino acid content of 718.20 g kg −1 , with the essential amino acid content reaching 252.00 g kg −1 . The highest amino acid content in mulberry leaf protein was glutamic acid, which plays an important role in signaling, regulating metabolism and other aspects of animal physiology 47 . The amino acid composition ratios of different proteins varied, but the nutritional value as feed additives mainly depended on the type, quantity and composition ratio of the essential amino acids contained.…”

“…The highest amino acid content in mulberry leaf protein was glutamic acid, which plays an important role in signaling, regulating metabolism and other aspects of animal physiology. 47 The amino acid composition ratios of different proteins varied, but the nutritional value as feed additives mainly depended on the type, quantity and composition ratio of the essential amino acids contained. As shown in Table 2, the ratio of EAA/TAA in the eight proteins was Cottonseed meal (0.42) ≈ Fish meal (0.42) > Bean pulp (0.41) ≈ Alfalfa (0.41) > Sample 8 (0.40) > Sample 13 (0.35).…”

Metabolism and Nutrition of L-Glutamate and L-Glutamine in Ruminants

“…At present, the National Research Council (NRC) has not established dietary requirements for preruminants or ruminants (e.g., calves, beef cattle, dairy cows, lambs, and ewes) for Glu or Gln [ 75 , 121 ]. However, there is evidence that preruminants, as well as adult sheep, goats, dairy cows, and cattle, require dietary Glu ( Table 5 ) and Gln ( Table 6 ) supplementation for maximal growth and production performance, as well as for optimal (particularly intestinal) health and function, as detailed in the following sections [ 122 , 123 , 124 , 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 , 135 , 136 , 137 , 138 , 139 , 140 , 141 , 142 , 143 , 144 , 145 , 146 , 147 , 148 , 149 , 150 , 151 , 152 , 153 , 154 , 155 , 156 , 157 , 158 , 159 , 160 , 161 , 162 , 163 , 164 , 165 , 166 ]. This represents a paradigm shift in ruminant nutrition.…”

Influence of management systems on severity of heat stress on reproductive performance of rams in the tropics – a review

“…Fermentation in the rumen plays an important role in the mitigation of heat stress in livestock. Fermentation in the rumen can be enhanced by supplementing with feed additives and increasing microbial diversity through, for example, Moringa oleifera (Al Mufarji et al, 2022), glutamate (Li et al, 2022) and Saccharomyces cerevisiae (Xue et al, 2022). The fermentation of wheat grain using Bioprotect TM a commercial starch and protein binding agent, can reduce the production of gas in addition to reducing the heart and respiration rates in lambs (Prathap et al, 2022).…”