BETA-SITOSTEROL DIETARY SUPPLEMENTATION IN DAIRY SHEEP MODIFIES MILK DELTA 9 DESATURASE INDEXES AND COCCIDIA LOAD

This research investigated the effects of dietary beta-sitosterol supplementation on productive performance, milk quality, and faecal parasitic load in dairy sheep. A total of 16 Lacaune sheeps in the mid-lactation phase were selected and randomly assigned to two homogeneous groups (n = 8) based on parity, body weight, body condition score (BCS), and milk yield. Both groups were fed the same diet, except that the treatment group received feed supplemented with 0.16% beta-sitosterol. The trial lasted 49 days, including a 14-day adaptation period followed by a 35-day experimental phase. Milk samples were collected individually once a week during morning milking, and pooled faecal samples were collected weekly from each group. Animal weight, milk yield, fat, and protein content were not affected by beta-sitosterol supplementation. Regarding milk fatty acid profile, an increase in palmitoleic acid (C16:1) was observed in the treated group (0.81%) versus control (0.72%). Additionally, a significant decrease (P < 0.05) in stearic acid (C18:0) content was observed in the treatment group (11.25%) compared with the control group (12.58%). The indices of the delta-9 desaturase enzyme showed a variation following dietary supplementation with beta-sitosterol, with significantly higher ratios observed in the treated group. Specifically, the C16:1 cis-9/ C16:0 ratio was significantly higher (P < 0.05) in the treatment group (0.02 vs 0.03); similarly, the C18:1 cis-9/ C18:0 ratio also increased, with a highly significant difference (P < 0.01) in the treated animals (1.40 vs 1.60). Parasitological analysis revealed a significant reduction (P < 0.05) in coccidia load in the treatment group, from 339 in the control group to 189 oocysts per gram (OPG) of treatment group. The results suggest that dietary beta-sitosterol supplementation may play a role in modulation of desaturase indexes in milk and may help in the control of gastrointestinal parasite. Further research is needed to clarify its mechanism of action.