Dietary glycine supplementation enhances postweaning growth and meat quality of pigs with intrauterine growth restriction

Abstract

Pigs with intrauterine growth restriction (IUGR) have suboptimum growth performance and impaired synthesis of glycine (the most abundant amino acid in the body). Conventional corn- and soybean meal-based diets for postweaning pigs contain relatively low amounts of glycine and may not provide sufficient glycine to meet requirements for IUGR pigs. This hypothesis was tested using 52 IUGR pigs and 52 litter mates with normal birth weights (NBW). At weaning (21 d of age), IUGR or NBW pigs were assigned randomly to one of two nutritional groups: supplementation of a corn–soybean meal-based diet with either 1% glycine plus 0.19% cornstarch or 1.19% L-alanine (isonitrogenous control). Feed consumption and body weight (BW) of pigs were recorded daily and every 2 or 4 wks, respectively. All pigs had free access to their respective diets and clean drinking water. Within 1 wk after the feeding trial ended at 188 d of age, blood and other tissue samples were obtained from pigs to determine concentrations of amino acids and meat quality. Neither IUGR nor glycine supplementation affected (P > 0.05) feed intakes of pigs per kg BW. The final BW, gain:feed ratio, carcass dressing percentages, and four-lean-cuts percentages of IUGR pigs were 13.4 kg, 4.4%, 2%, and 15% lower (P < 0.05) for IUGR pigs than NBW pigs, respectively. Compared with pigs in the alanine group, dietary glycine supplementation increased (P < 0.05) final BW, gain:feed ratio, and meat a* value (a redness score) by 3.8 kg, 11%, and 10%, respectively, while reducing (P < 0.05) backfat thickness by 18%. IUGR pigs had lower (P < 0.05) concentrations of glycine in plasma (−45%), liver (−25%), jejunum (−19%), longissimus dorsi muscle (−23%), gastrocnemius muscle (−26%), kidney (−15%), and pancreas (−6%), as compared to NBW pigs. In addition, dietary glycine supplementation increased (P < 0.05) concentrations of glycine in plasma and all analyzed tissues. Thus, supplementing 1% of glycine to corn–soybean meal-based diets improves the growth performance, feed efficiency, and meat quality of IUGR pigs.

Dietary glycine supplementation enhances syntheses of creatine and glutathione by tissues of hybrid striped bass (Morone saxatilis ♀ × Morone chrysops ♂) fed soybean meal-based diets

“…Notably, GSH is the most important non-enzymatic antioxidant in animals, whereas creatine helps to store ATP in the form of phosphocreatine for physiological processes such as muscle contractions, protein synthesis, and nutrient transport. Emerging evidence indicates that the endogenous synthesis of glycine may not meet the demand of farmed animals (e.g., HSB and growing pigs) under various nutritional and physiological conditions [ 13 , 14 , 27 ]. Although SBM has a balanced profile for most AAs, this feed ingredient contains much less glycine than fishmeal [ 19 ].…”

“…Growing-finishing pigs cannot produce sufficient GSH in the liver, kidneys, and small intestine, when fed SBM-based diets [ 46 ]. Thus, dietary supplementation with 1% glycine to these animals enhanced this synthetic pathway [ 15 ] and whole-body growth [ 27 ], while reducing oxidative stress in their tissues [ 15 ]. Likewise, dietary supplementation with GSH improves the growth, anti-oxidative capacity, disease resistance and gut morphology in juvenile Atlantic salmon [ 33 ], common carp [ 47 ], triploid rainbow trout [ 48 ], shrimp [ 49 ], and crabs [ 50 ].…”

Integrated Analysis of Transcriptome and Metabolome Profiles in the Longissimus Dorsi Muscle of Buffalo and Cattle

“…The transcriptomic and metabolomic data revealed that both omics KEGG pathways were significantly enriched in glycine, serine, and threonine metabolism, which may be related to tenderness. Glycine is the main structural unit of connective tissue and can bind with collagen protein to enhance the tenderness of meat [32]. Threonine is an important component of myofibrillar protein and collagen protein, which contributes to the increase in tenderness and flavor [33].…”