Novel Insights into the Differences in Nutrition Value, Gene Regulation and Network Organization between Muscles from Pasture-Fed and Barn-Fed Goats

Abstract

The physiological and biochemical characters of muscles derived from pasture-fed or barn-fed black goats were detected, and RNA-seq was performed to reveal the underlying molecular mechanisms to identify how the pasture feeding affected the nutrition and flavor of the meat. We found that the branched chain amino acids, unsaturated fatty acids, and zinc in the muscle of pasture-fed goats were significantly higher than those in the barn-fed group, while the heavy metal elements, cholesterol, and low-density lipoprotein cholesterol were significantly lower. RNA-seq results showed that 1761 genes and 147 lncRNA transcripts were significantly differentially expressed between the pasture-fed and barn-fed group. Further analysis found that the differentially expressed genes were mainly enriched in the myogenesis and Glycerophospholipid metabolism pathway. A functional analysis of the lncRNA transcripts further highlighted the difference in fatty acid metabolism between the two feeding models. Our study provides novel insights into the gene regulation and network organization of muscles and could be potentially used for improving the quality of mutton.

Review of Feeding Systems Affecting Production, Carcass Attributes, and Meat Quality of Ovine and Caprine Species

“…This implies that pasture grazing enhances the meat flavor of goat kids. Yang et al [ 87 ] also showed that, compared with their stall-fed counterparts, pasture-grazed goat kids had superior flavor in regard to the longissimus muscle, which can be attributed to lower isoleucine and leucine contents. These outcomes could be because walking during pasture grazing promotes lipid oxidation in meat, increasing the synthesis of aldehyde and alcohol compounds [ 87 ] and resulting in different FA compositions of the meat [ 88 ].…”

“…Yang et al [ 87 ] also showed that, compared with their stall-fed counterparts, pasture-grazed goat kids had superior flavor in regard to the longissimus muscle, which can be attributed to lower isoleucine and leucine contents. These outcomes could be because walking during pasture grazing promotes lipid oxidation in meat, increasing the synthesis of aldehyde and alcohol compounds [ 87 ] and resulting in different FA compositions of the meat [ 88 ]. In addition, compared with intensive feeding on concentrate diets, grazing pasture with concentrate supplementation exhibited a similar flavor effect on goat kids [ 53 ], possibly because of the similar meat IMF content between the two feeding systems [ 89 , 90 ].…”

“…These results can be explained by the fact that grazing increases forage intake but reduces concentrate intake, which, in turn, increases the levels of n-3 PUFA and decrease SFA levels. The SFA levels in the longissimus muscle of goat kids are equal to or lower than kids grazed on pasture and those under stall-feeding conditions [ 52 , 87 ]. However, the levels of PUFA, n-3 PUFA, and n-6 PUFA were comparable or higher in kids grazed on pasture [ 52 , 87 ].…”

“…The SFA levels in the longissimus muscle of goat kids are equal to or lower than kids grazed on pasture and those under stall-feeding conditions [ 52 , 87 ]. However, the levels of PUFA, n-3 PUFA, and n-6 PUFA were comparable or higher in kids grazed on pasture [ 52 , 87 ]. In addition, the levels of SFA, PUFA, n-3 PUFA, and n-6 PUFA were comparable between the meat of kids that are grazed/supplementation-fed and those fed concentrate diets [ 29 , 111 ].…”

“…These results could be due to the fact that higher energy intake promotes SFA synthesis and increases the C18:3n3 ratio in herbage, while higher forage intake promotes the growth of fibrolytic microorganisms responsible for the rumen hydrogenation process, increasing the production of CLAs. Regarding goat kids, C18:2n-6, ALA, GLA, and DHA were equal or higher, while C14:0 and C16:0 contents were lower in goat kid meat grazed only on pasture than in those fed on concentrates [ 52 , 87 ]. These findings indicate that the meat of kids grazed on pasture has higher levels of healthy FAs than those fed with concentrates.…”