Rumen metabolism and gas formation in sheep fed different fat sources

The aim of the work was to study the effect of various fat sources in sheep nutrition on the indices of rumen digestion and the release of methane and carbon dioxide using the in vivo method. The experiment was conducted in the physiological yard of the L.K. Ernst Federal Research Center for Animal Husbandry in 2024 on Romanov rams and crossbreeds with Katadin with chronic rumen fistulas using the group-period method. During the control period, animals received the main diet (hay and concentrates), in the I experimental period – in addition to it, palm oil, in the II experimental – sunflower oil, in the III experimental – fat from the larvae of the Hermetia illucens fly at a dosage of 0.5 % of the DM (dry matter) of the diet (7.5 g per day). Animals received the daily amount of feed in 2 doses. At the end of each period, all animals were examined for rumen metabolism dynamics and gas emission in vivo. Supplementation of various fat sources in the specified dosage did not have a negative effect on the consumption of basic feed. The use of fly larvae fat in sheep diet contributed to an increase in the concentration of VFA (volatile fatty acids) by 29 % (p<0.01), a decrease in the level of ammonia nitrogen by 12.91 %. The use of palm and vegetable fats led to a decrease in the concentration of ammonia nitrogen in the rumen by 28.7 % (p<0.05) and 29.5 % (p<0.05) compared to the control, respectively. During the control period, 20.66 l of methane were excreted from the sheep's body, in the I experimental period it was 12.0 % less (18.18 l), in the II experimental period – 6.20 % less (19.38 l), in the III experimental period – 20.33 % less (16.46 l) (p<0.01). Using additional fat sources in ruminant feed may be an effective way to reduce greenhouse gas emissions.