Intramuscular Fat Content In Longissimus Muscle Research Articles

Antibiotic affects the gut microbiota composition and expression of genes related to lipid metabolism and myofiber types in skeletal muscle of piglets

BackgroundEarly-life antibiotic administration is known to affect gut microbiota and host adiposity, but the effects of antibiotic exposure on skeletal muscle properties remain unknown. The present study evaluated the changes in skeletal muscle properties including myofiber characteristics and composition, as well as intramuscular fat (IMF) content in skeletal muscle of piglets when exposed to a tylosin-containing diet.ResultsA total of 18 piglets (28 days of age) were randomly allocated into two groups: control basal diet (Control) and Control + 100 mg tylosin phosphate/kg of feed (Antibiotic). The trial lasted for 39 days. High-throughput amplicon sequencing revealed that no significant difference in initial gut microbiota composition was existed between Control and Antibiotic groups. Antibiotic administration increased body weight and growth rate and decreased feed to gain ratio of pigs (P < 0.05). The carcass lean and fat volumes of pigs were increased by the tylosin administration (P < 0.05). Antibiotic treatment increased myofiber density and the expression of genes related to type I and type IIb myofibers in longissimus muscle (P < 0.05). The IMF content in longissimus muscle was increased by antibiotic exposure (P < 0.05). Antibiotic administration increased expression of genes related to fatty acid uptake and de novo synthesis, and decreased expression of genes related to triglyceride hydrolysis (P < 0.05). Tylosin administration affected taxonomic distribution and beta diversity of the caecal and colonic microbiota of piglets.ConclusionThese results confirm that the growth performance, myofiber composition and muscle lipid metabolism are affected by antibiotic administration, which may be associated with an altered gut microbiota, suggesting that the gut microbiota could be served as a potential target for modulating skeletal muscle properties of host.

The Relation Between Intramuscular Fat Level in the Longissimus Muscle and the Quality of Pig Carcasses and Meat

Abstract This study evaluated the effect of intramuscular fat (IMF) content on the quality of pig carcass and meat. One hundred and twenty right half-carcasses of crossbred pigs (Pietrain × Duroc boars and Polish Large White × Polish Landrace sows) from a commercial farm were divided into two groups depending on the content of IMF in the longissimus muscle (LM): LIMF - lower content (mean 2.05% IMF; 28 gilts and 30 barrows) and HIMF - higher content (mean 3.08% IMF; 32 gilts and 30 barrows) were used. Pigs with a higher IMF content in LM (HIMF group) had a significantly lower (P≤0.01) percentage of lean meat in carcass, loin muscle area, level of polyunsaturated fatty acids (PUFAs) and PUFAs/SFAs ratio, whereas backfat thickness, content of cholesterol in LM, levels of saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) were significantly greater (P≤0.01) than those in pigs with lower IMF content (LIMF group).

Expression profiles of myostatin and calpastatin genes and analysis of shear force and intramuscular fat content of yak longissimus muscle

The main objective of this study was to reveal the expression profiles of two negative regulators, myostatin (MSTN) and calpastatin (CAST)genes, of skeletal muscle growth in highland yaks (Bos grunniens). mRNA levels of both genes were quantified in different yak tissues by semi-quantitative RT-PCR to reveal the tissue expression pattern, and real-time quantitative RT-PCR was employed to compare the mRNA levels of MSTN and CAST in longissimus muscles of yaks at different ages and adult Yellow cattle. Intramuscular fat (IMF) content, tenderness and pH of longissimus muscle of yaks at different ages and of adult Yellow cattle were also measured. The results showed that MSTN and CAST expressions have tissue specificity and both exhibited a high level in longissimus muscle and a low level in adipose tissue. Yak calves had lower mRNA levels of both MSTN and CAST in longissimus muscle compared with adult yaks. The analysis of meat quality traits of longissimus muscle showed that the shear forces of raw longissimus muscle of yak calves were significantly lower than those of adult yaks and Yellow cattle, no significant difference was found between adult yaks and Yellow cattle of similar age. IMF content in longissimus muscle was lower in yaks than in Yellow cattle. Although yaks were smaller in body size than Yellow cattle, adult yaks showed lower levels of MSTN and similar level of CAST mRNA in longissimus muscle compared to Yellow cattle. These data indicate that the expression of both MSTN and CAST in longissimus muscle differs between adult yaks and yak calves, and the yak longissimus muscle shows a lower IMF content compared to cattle. &amp;nbsp;