Comparison of muscle fiber characteristics and meat quality between newborn and adult Haimen goats

Analyses of the physicochemical and sensory characteristics of black goat triceps brachii muscle based on slaughter age

In this study, we aimed to analyze the effects of slaughter age on black goat meat's physicochemical and nutritional characteristics. Goats (age: 3, 6, 9, 12, 24, and 36 months) reared under identical conditions were used in this study. The key parameters were analyzed, including color, cooking yield, shear force, free amino acid (FAA) levels, free fatty acid levels, and sensory attributes. Hue values decreased, whereas redness increased with age. Umami and sweet FAA levels increased with age, and bitter FAA levels increased from 9 months. The flavor scores increased with age up to 9 months. Off-flavors were significantly higher in goats aged 24 and 36 months than in those aged 3 and 6 months. Goats aged 9 and 12 months had significantly higher texture scores than those aged 3, 6, and 36 months. Overall, our findings suggest that goats aged 9 and 12 months exhibit the best sensory qualities.

Effects of Ginger Straw Silage with Enzymes on Growth Performance, Digestion and Metabolism, Meat Quality and Rumen Microflora Diversity of Laiwu Black Goat

Laiwu black goats comprise an excellent local germplasm resource; however, a shortage of feed resources has led to the application of unconventional feed. Ginger straw feed has good physiological effects, but research on this feed source for ruminant animals is lacking. The aim of this study was to determine the effects of enzymatic silage ginger straw on Laiwu black goat performance. The experiment used an independent sample t-test analysis method; 24 healthy Laiwu black goats with a body weight of 20.05 ± 1.15 kg and age of 5.67 ± 0.25 months were randomly divided into two groups with three replicates (bars) per group and four goats per replicate. The experimental diet was composed of mixed concentrate, silage, and garlic peel at a 2:7:1 ratio. The silage used in the two groups was whole corn silage (CON group) and 60% whole corn silage plus 40% enzymatic silage ginger straw (SG group), and the other components were identical. Daily feed intake/daily gain (F/G) was significantly higher in the SG group than in the CON group (p < 0.05), but there were no significant differences in dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) digestibility between the groups. The shear force, cooking loss, centrifugal loss, and pressure loss of the longissimus dorsi muscle group were significantly lower in the SG than in the CON group (p < 0.05). Compared with those in the CON group, the serum and liver total antioxidant capacity was significantly increased in the SG group, and in the liver, the O2·-, malondialdehyde, and OH· contents were significantly decreased. Collectively, the rumen fluid microbial diversity was changed in the SG group. It was concluded that enzymatic silage ginger straw usage instead of 40% whole silage corn as feed for Laiwu black goats can significantly improve the muscle quality, antioxidant capacity, and intestinal flora, with no adverse effects on production performance. In conclusion, our study provides a basis for ginger straw processing and storage and its rational application in the Laiwu black goat diet.

Effect of Guanidinoacetic Acid on Production Performance, Serum Biochemistry, Meat Quality and Rumen Fermentation in Hu Sheep

Guanidinoacetic acid (GAA) can effectively improve the metabolism of energy and proteins by stimulating creatine biosynthesis. We present a study exploring the impact of GAA on production performance, serum biochemistry, meat quality and rumen fermentation in Hu sheep. A total of 144 weaned male Hu sheep (body weight 16.91 ± 3.1 kg) were randomly assigned to four groups with three replicates of twelve sheep in each group. The diets were supplemented with 0 (CON), 500 (GAA-1), 750 (GAA-2) and 1000 mg/kg (GAA-3) of GAA (weight of feed), respectively. After a comprehensive 90-day experimental period, we discovered that the supplementation of GAA had a remarkable impact on various muscle parameters. Specifically, it significantly enhanced the average daily growth (ADG) of the animals and improved the shear force and fiber diameter of the muscle, while also reducing the drip loss and muscle fiber density. Furthermore, the addition of GAA to the feed notably elevated the serum concentrations of high-density lipoprotein cholesterol (HDL-C), total protein (TP) and globulin (GLB), as well as the enzyme activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Concurrently, there was a decrease in the levels of triglycerides (TG) and malondialdehyde (MDA) in the serum. In addition, GAA decreased the pH and the acetate-to-propionate ratio and increased the total volatile fatty acids (TVFA) and ammoniacal nitrogen (NH3-N) levels of rumen fluid. Additionally, GAA upregulated acetyl-CoA carboxylase (ACC) gene expression in the Hu sheep's muscles. In conclusion, our findings suggest that GAA supplementation not only enhances muscle quality but also positively affects serum biochemistry and ruminal metabolism, making it a potential candidate for improving the overall health and performance of Hu sheep.

Preliminary studies on the molecular mechanism of intramuscular fat deposition in the longest dorsal muscle of sheep

BACKGROUND

Intramuscular fat content is an important index reflecting the quality of mutton, which directly affects the flavor and tenderness of mutton. Livestock and poultry intramuscular fat content is influenced by genetics, nutritional level, and environmental factors. Key regulatory factors play a crucial role in intramuscular fat deposition. However, there is a limited amount of research on the identification and function of key genes involved in intramuscular fat content deposition specifically in sheep.

RESULTS

Histological differences in the longest dorsal muscle of the small-tailed frigid sheep increased in diameter and decreased in several muscle fibers with increasing monthly age; The intramuscular fat content of the longest dorsal muscle of the small-tailed cold sheep varied with age, with a minimum of 1 month of age, a maximum of 6 months of age, and a minimum of 12 months of age. Transcriptomic sequencing and bioinformatics analysis revealed a large number of differential genes in the longest dorsal muscles of little-tailed billy goats of different months of age, which were enriched in multiple GO entries and KEGG pathways. Among them, the pathway associated with intramuscular fat was the AMPK signaling pathway, and the related genes were PPARGC1A and ADIPOQ; Immunohistochemical studies showed that PPARGC1A and ADIPOQ proteins were expressed in connective tissues, cell membranes, and, to a lesser extent, the cytoplasm of the longest dorsal muscle of the little-tailed frigid sheep; Real-time PCR and Western Blot validation showed that PPARGC1A and ADIPOQ were both expressed in the longest dorsal muscle of the little-tailed frigid sheep at different ages, and there were age differences in the amount of expression. The ADIPOQ gene was negatively correlated with the intramuscular fat content of the longest dorsal muscle, and the PPARGC1A gene was positively correlated with the intramuscular fat content of the longest dorsal muscle; As inferred from the above results, the ADIPOQ gene was negatively correlated with the intramuscular fat content of the longest dorsal muscle (r = -0.793, P < 0.05); and the PPARGC1A gene was positively correlated with the intramuscular fat content of the longest dorsal muscle r = 0.923, P < 0.05).

CONCLUSIONS

Based on the above results, it can be inferred that the ADIPOQ gene is negatively correlated with the intramuscular fat content of the longest back muscle (r = -0.793, P < 0.05); the PPARGC1A gene is positively correlated with the intramuscular fat content of the longest back muscle (r = 0.923, P < 0.05).

circUSP13 facilitates the fast-to-slow myofiber shift via the MAPK/ERK signaling pathway in goat skeletal muscles

Understanding how skeletal muscle fiber proportions are regulated is essential for understanding muscle function and improving the quality of mutton. While circular RNA (circRNA) has a critical function in myofiber type transformation, the specific mechanisms are not yet fully understood. Prior evidence indicates that circular ubiquitin-specific peptidase 13 (circUSP13) can promote myoblast differentiation by acting as a ceRNA, but its potential role in myofiber switching is still unknown. Herein, we found that circUSP13 enhanced slow myosin heavy chain (MyHC-slow) and suppressed MyHC-fast expression in goat primary myoblasts (GPMs). Meanwhile, circUSP13 evidently enhanced the remodeling of the mitochondrial network while inhibiting the autophagy of GPMs. We obtained fast-dominated myofibers, via treatment with rotenone, and further demonstrated the positive role of circUSP13 in the fast-to-slow transition. Mechanistically, activation of the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathway significantly impaired the slow-to-fast shift in fully differentiated myotubes, which was restored by circUSP13 or IGF1 overexpression. In conclusion, circUSP13 promoted the fast-to-slow myofiber type transition through MAPK/ERK signaling in goat skeletal muscle. These findings provide novel insights into the role of circUSP13 in myofiber type transition and contribute to a better understanding of the genetic mechanisms underlying meat quality.