Yan Duan

The transition from grazing to captive rearing resulted in a significant decline in meat quality. To enhance the quality of meat from captive sheep, we examined the impact of exercise on Sunit lambs. The lambs, with similar body weight and aged 3 months underwent a 90-day period of thought-driven exercise. At the end of the exercise period, we collected colonic contents, epithelial tissues, and the longissimus dorsi muscle, and recorded slaughter performance. Exercise was found to have a significant impact on the content of short-chain fatty acids in the colon. Additionally, it generally reduced the mRNA expression of fatty acid absorption transporter genes in the colonic epithelium and lipid metabolism-related genes in the longissimus dorsi muscle. Furthermore, exercise significantly affected the content of fatty acids in the longissimus dorsi muscle of Sunit lambs, and increased its dressing percentage. Exercise influences the composition of fatty acids of the longissimus dorsi muscle and improves dressing percentage by affecting the digestion, absorption, and metabolism of lipids in Sunit lambs. This could be profitable for the livestock industry, and could alter the nutrition and flavor of lamb meat.

In this study, the safety of fermented lamb sausage was examined. The aim was to investigate the effect of Lactiplantibacillus plantarum X22-2 (LP X22-2) on the quality of, and biogenic amine (BA) formation in, fermented lamb sausages during fermentation, maturation, and storage. The results showed that LP X-22 was effective in increasing the number of lactic acid bacteria (LAB) and in significantly inhibiting the formation of putrescine, histamine, cadaverine, and tyramine in fermented lamb sausage (p < 0.05). The total volatile basic nitrogen (TVB-N) content, peroxide value (POV) of fat, pH, water activity (AW), and viscosity were lower in the LF group compared to other groups (commercial starter group—CF, and natural fermentation group—NF) (p < 0.05). Furthermore, sensory evaluation and texture profile analysis (TPA) indicated that LP X-22 significantly increased the a* value, chewiness, and hardness of the sausages (p < 0.05). Therefore, LP X-22 is recommended as a natural and safe protective culture for preserving fermented lamb sausage and maintaining the color of the sausages while improving their sensory quality and inhibiting the accumulation of BAs.

The development of animal husbandry is closely related to the meat quality of small ruminants. Intestinal metabolites and the muscle fiber types of lambs are important factors that affect their meat quality, but few studies have examined the regulation of the "intestinal muscle axis" by probiotics. In this study, 12 Sunit lambs were divided into a control group (C) and a probiotics group (P). The gene expressions of the myosin heavy chain, metabolic enzyme activity, and short-chain fatty acids in the intestines were analyzed using gas chromatography-mass spectrometry (GC-MS) and quantitative real-time PCR. The results showed that levels of propionic acid and butyric acid in the intestines of group P were significantly higher than in group C (p < 0.05). In addition, probiotics increased the number and area ratio of type I muscle fibers. They also increased the mRNA expression of MyHC IIA and the activity of malate dehydrogenase (MDH) and succinate dehydrogenase (SDH). Propionic acid was negatively correlated with the number ratio of type IIB muscle fibers. Butyric acid was found to be significantly positively correlated with the number ratio of type IIA muscle fibers. Cooking loss, pH_24h, and shear force decreased significantly in group P. In conclusion, intestinal metabolites (SCFAs) altered the activity of oxidative-myofibril-metabolizing enzymes and the expression of myosin heavy-chain type IIA, reduced the meat shear values, and improved meat tenderness. This study provides a new basis for improving the production and meat quality of small ruminants.

To improve the meat quality of Nei Mongol mutton and the benefits for farmers, we selected Australian salmon hybrid lambs as experimental subjects to investigate the effects of Allium mongolicum Regel powder (AMR) and yeast-fermented distiller’s grains (DGS) on their production performance and economic efficiency. The results showed that the DGS group had higher kidney index, the AMR group had better meat quality, and the economic efficiency ratio of DGS and AMR was 2.08. In conclusion, both feeds had no adverse effects on the production performance of lambs, and the DGS group had greater potential for promotion.

The probiotic fermentation of lamb liver paste is a new method with which to utilize sheep by-products and address the issue of waste. In this study, a pH meter, chromaticity meter, texture analyzer, and gas chromatograph–mass spectrometer (GC–MS) were used to determine various indicators. The objective was to investigate the effect of fermentation on the physical properties and aroma of lamb liver paste. The results showed that the L* (brightness), a* (redness), and b* (yellowness) of the samples were significantly higher in the starter fermentation group than in the other two groups after storage for 0, 1, 7, 14, 21, and 28 days (p < 0.05). In addition, cohesiveness, adhesion, and chewiness were lower in the starter fermentation group after 7 days (p < 0.05). TVB-N and fat were lower in the starter fermentation group compared to the sterilization group at 28 days. pH was significantly lower in the starter fermentation group at the beginning of storage, and lactic acid bacteria numbers were significantly higher than in the sterilization groups (p < 0.05). Important aroma compounds, such as 2-undecenal, 1-octen-3-ol, and anethole, were significantly higher in the starter fermentation group than in the sterilization group (p < 0.05). Fermented lamb liver paste is a new by-product that exhibits a high degree of freshness and a low degree of fat oxidation during storage. This study provides a theoretical basis for future industrial production.

Sheep crude tail fat has unique nutritional values and is used as a raw material for high-quality natural oil. The purpose of this study was to investigate the effects of probiotics on the metabolites and flavor of sheep crude tail fat. In this study, 12 Sunit sheep were randomly divided into an experimental group (LTF, basal feed + Lactiplantibacillusplantarum powder) and a control group (CTF, basal feed). The results of sheep crude tail fat analysis showed that blood lipid parameters were significantly lower and the expression of fatty acid synthase and stearoyl-CoA desaturase genes higher in the LTF group than in the CTF group (p < 0.05). Metabolomic analysis via liquid chromatography–mass spectrometry showed that the contents of metabolites such as eicosapentaenoic acid, 16-hydroxypalmitic acid, and L-citrulline were higher in the LTF group (p < 0.01). Gas chromatography–mass spectrometry detection of volatile flavor compounds in the tail fat showed that nonanal, decanal, and 1-hexanol were more abundant in the LTF group (p < 0.05). Therefore, Lactiplantibacillus plantarum feeding affected blood lipid parameters, expression of lipid metabolism-related genes, tail fat metabolites, and volatile flavor compounds in Sunit sheep. In this study, probiotics feeding was demonstrated to support high-value sheep crude tail fat production.

The Inner Mongolia Autonomous Region is the region with the highest mutton production in China, but researchers know very little about the genetic evolution of local sheep. In this experiment, whole-genome resequencing technology was used to investigate the genetic distance and single nucleotide polymorphism (SNP) of Chahar sheep, Ujimqin sheep and Xiqi sheep. The results showed that the distribution of SNPs in different regions of the genome was different, thus affecting the function of some genes. Insertion-Deletion (INDEL) also suggested an evolutionary distance between these three types of sheep. The genetic distance between Chahar sheep and the other two types of sheep is relatively far. During the construction of three sheep differential loci, it was found that they could be distinguished by the difference of bases at a certain position on the three chromosomes, which improved the identification of mutton. This suggests that the differences in meat quality between the three types of sheep are not only due to differences in the living environment but also may be influenced by genetic evolution. The research on differential genes can improve the data and theoretical basis for future precise nutrition.