Effects of Lysolecithin on Growth Performance, Nutrient Digestibility, Serum Biochemical Indices, and Rumen Environment in Holstein Calves

This study was to evaluate the effects of lysolecithin on the growth performance, serum biochemical indices, and rumen environment of Holstein calves. A total of 26 calves were divided into a control group with a basal diet (CON) and a treatment group that added 5 g/d lysolecithin (LY). Compared to the CON, the proportion of feces in the middle sieve was higher, and the proportion of the bottom sieve was lower in the LY (<i>p</i> < 0.05). Serum biochemical parameters indicated that the LY had higher albumin, total antioxidant capacity, and total cholesterol, whereas non-esterified fatty acid, blood urea nitrogen, and triglyceride were lower than the CON (<i>p</i> < 0.05). The NH₃-N of rumen fluid in the LY was lower than that of the CON (<i>p</i> < 0.05). The rumen fluid percentage of butyrate, iso-butyrate, valerate, and iso-valerate in the LY was higher than in the CON (<i>p</i> < 0.05), with a tendency for lower propionate compared to the CON (<i>p</i> < 0.10). In the rumen microorganism, the abundance of <i>Ruminococcu</i>s in the LY was higher than in the CON (<i>p</i> < 0.05). Mantel test indicated that the percentage of acetate was found significantly positively correlated with <i>Candidatus_Saccharimonas</i>, whereas propionate exhibited positive correlations with <i>Ruminococcus_gauvreauii_group</i>, <i>Candidatus_Saccharimonas</i>, and <i>unclassified Lachnospiraceae</i> (<i>p</i> < 0.05). Additionally, the <i>NK4A214_group</i> showed a significant positive correlation with the acetate/propionate, and the concentration of iso-valerate was positively correlated with <i>norank_f__norank_o__Clostridia_UCG-014</i> (<i>p</i> < 0.05). In summary, dietary lysolecithin supplementation could positively influence the rumen microbial community, enhance rumen fermentation, and improve antioxidant ability, without affecting growth performance in Holstein calves.