Key points are not available for this paper at this time.
Rumen microbes govern energy supply and nitrogen use in sheep. α-Ketoglutarate (AKG) links carbon and nitrogen metabolism and may support microbial synthesis, yet its in vivo effects on fermentation, digestibility, and antioxidant status in fattening lambs remain unclear. This study investigated the effects of AKG and its calcium salt (Ca-AKG) on growth performance, antioxidant capacity, nutrient digestibility, rumen fermentation, and rumen microbiota in fattening Hu lambs. Eighteen 3-month-old male Hu lambs (22.2 ± 1.08 kg) were randomly assigned into three groups (n = 6): (1) control group, fed a basal diet; (2) AKG group, fed the basal diet + 0.5% AKG (DM basis); and (3) Ca-AKG group, fed the basal diet + 0.5% Ca-AKG (DM basis). The experimental period lasted 9 weeks, including a 2-week adaptation phase followed by a 7-week measurement period. No treatment × week interaction was observed for growth performance, rumen fermentation, or blood biochemical parameters (P > 0.05). AKG tended to increase average daily gain (ADG) and gain-to-feed ratio (G: F) in fattening Hu lambs (0.05 0.10). In contrast, Ca-AKG improved DM intake, ADG, G: F, and final BW (P 0.05). Both AKG and Ca-AKG reduced plasma bicarbonate and glucose but increased triglycerides (P 0.05). Ca-AKG decreased superoxide dismutase activity (P 0.05); however, it enhanced both enzymes at week 7 (P 0.05). However, Ca-AKG increased Bacteroidetes and decreased Firmicutes at the phylum level (P < 0.05), elevated Prevotella and Prevotellaceae-UCG-003, and reduced Quinella, Christensenellaceae-R-7 group, and Aeromonas at the genus level. In summary, Ca-AKG more effectively promotes VFA synthesis, enhances plasma antioxidant capacity, and improves growth performance than AKG in fattening Hu lambs.
Duan et al. (Tue,) studied this question.