Improving feed efficiency is crucial to the animal industry. Residual feed intake (RFI) is now regarded as an index of feed efficiency evaluation and is independent of growth characteristics. Our study aims to explore the alterations in growth performance and nutrient digestion in Hu sheep with different RFI phenotypes. Sixty-four male Hu sheep (body weight = 24.39 ± 1.12 kg; postnatal days = 90 ± 7.9) were selected for the study. After an evaluation period of 56 days and power analysis, samples were collected from 14 low RFI (L-RFI group, power = 0.95) and 14 high RFI sheep (H-RFI group, power = 0.95). The L-RFI sheep yielded a lower (P < 0.05) feed conversion ratio and dry matter intake; however, both groups exhibited similar average daily gain (P > 0.05). The acid detergent fiber, neutral detergent fiber, organic matter, and crude protein apparent digestibility were higher (P < 0.05) in L-RFI sheep. N intake and fecal N output (% of N intake) were lower (P < 0.05) and N retention (% of N intake) was higher (P < 0.05) in L-RFI sheep, whereas no difference (P > 0.05) was found in urine N output (% of N intake) between the 2 groups. Furthermore, L-RFI sheep gave lower (P < 0.05) serum glucose concentrations and higher (P < 0.05) non-esterified fatty acid concentrations. Meanwhile, a lower ruminal acetate molar proportion (P < 0.05) and higher propionate molar proportion (P < 0.05) were observed in L-RFI sheep. In summary, these results revealed that despite having lower dry matter intake, L-RFI sheep possess higher nutrient digestibility, N retention, ruminal propionate production and serum glucose utilization, in order to meet energy demands. Selection for low RFI sheep could reduce feed costs, which in turn provides economic benefits to the sheep industry.

Dairy mastitis is an inflammatory reaction caused by mechanical injury and stress within the mammary gland, during which microbial changes and abnormal lipid metabolism occur. However, the underlying mechanism is still unclear. The present study used a combination of 16S rDNA sequencing technology and lipidomics techniques to reveal the effects of mastitis on lactic microbiota and metabolites in the milk of dairy cows. Twenty multiparous Holstein dairy cows (2–3 parities) with an average body weight of 580 ± 30 kg were selected for this study. The dairy cows were allocated to control group (5 × 10⁶ cells /mL) based on the somatic cell count. The results showed that mastitis caused a decrease trend in milk production (p = 0.058). The results of the 16 s sequencing indicated a significant decrease (p < 0.05) in the number of Proteobacteria, Tenericutes colonized in mastitis milk, and the number of Firmicutes, Bacteroidetes and Actinobacteria communities increased significantly (p < 0.05). The lipidomics results revealed that the changes in lipid content in mastitis milk were correlated with arachidonic acid metabolism, α -linolenic acid metabolism and glycerol phospholipid metabolism. The results showed that mastitis may cause abnormal lipid metabolism in milk by regulating the diversity of milk microflora, and ultimately affect the milk quality.

Objective: Mulberry (Morus alba) leaf (ML) is a high-quality feed source for ruminants, while it is unclear whether it can enhance the growth performance and meat quality of Xiangdong black goats.Methods: In this study, we investigated the effects of ML supplementation (0%, 5%, 10%, 15%, and 20%) on the growth performance, serum variables, and the profiles of amino acids and fatty acids in the muscle of Xiangdong black goats.Results: Results showed that the final body weight, initial and final dry matter intake, and average daily gain increased linearly and quadratically with the increasing ML content (p<0.05). The serum concentrations of total antioxidant capacity (T-AOC) increased linearly, while immunoglobulin G (IgG) increased quadratically with the increasing ML content (p<0.05). Conversely, the saturated fatty acids (SFA) content in meat decreased linearly with the increasing ML content (p<0.05). Compared to goats without ML supplementation, goats fed with 15% ML showed significant increases in serum concentrations of T-AOC, superoxide dismutase, catalase, and IgG (p<0.05). Furthermore, goats fed with 20% ML displayed significant decreases in SFA (C18:0) content, compared to goats without ML supplementation (p<0.05).Conclusion: These results suggest that ML supplementation promotes the growth performance of goats. A diet containing 15% ML showed better effects in promoting antioxidant and immunomodulatory activities, while a diet with 20% ML was more effective in enhancing meat flavor in Xiangdong black goats.

Cadmium (Cd) is an environmental pollutant, widely existing in soil, and can be absorbed and accumulated by plants. Hunan Province exhibits the worst cadmium contamination of farmland in China. Ruminants possess an abundant microbial population in the rumen, which enables them to tolerate various poisonous plants. To investigate whether the rumen microbiota could respond to Cd and mitigate the toxicity of Cd-accumulated maize to ruminants, 6-month-old cattle were fed with 85.82% (fresh basis) normal whole-plant maize silage diet (CON, n = 10) or Cd-accumulated whole-plant maize silage diet (CAM, n = 10) for 107 days. When compared to the CON cattle, CAM cattle showed significantly higher gain-to-feed ratio and an increased total bacterial population in the rumen, but a decreased total bacterial population in the colon. CAM cattle had higher relative abundance of Prevotella and Lachnospiraceae ND3007 group in the rumen, and Lachnospiraceae NK4A136 group and Clostridia vadinBB60 group in the colon. Notably, microbial correlations were enhanced in all segments of CAM cattle, especially Peptostreptococcaceae in the jejunum. Transcriptome analysis revealed down-regulation of several immune-related genes in the rumen of CAM cattle, and differentially expressed genes in the rumen were mostly involved in immune regulation. These findings indicated that feeding Cd-accumulated maize diet with a Cd concentration of 6.74 mg/kg dry matter (DM) could stimulate SCFA-related bacteria in the rumen, induce hormesis to promote weight gain, and improve energy utilization of cattle.