Two experiments was implemented to determine nutrient digestibility, rumen
environment, nitrogen retention and in vitro and in vivo methane and carbon dioxide
production of Lai Sind cattle effected by catfish oil (CFO) supplementation. In the
first experiment, it was a complete randomized design with 6 treatments and 3
replications. The treatments were 0, 1, 2, 3, 4, 5 % of CFO in the total substrate (DM
basis) by using a glass syringe system and Para grass (Brachiara mutica) used as the
main substrate. In the second experiment, it was a 4x4 Latin square design with 4
growing crossbred cattle (Red Sindhi x local cattle) and 4 treatments. The treatments
were the supplementation of CFO at a level of 0, 1, 2 and 3% corresponding to the
CFO0, CFO1, CFO2 and CFO3 treatments. In all the treatments rice straw was fed ad
libitum, while concentrate feed was fed at a level of 1 kg per 150 kg LW. The results
showed that the in vitro CH4 and CO2 production from 0-48 h were significantly
different (Pwhen increasing CFO levels from 0 to 5%. In Exp 2 the nutrient intakes and digestion
of cattle supplemented with different levels of catfish oil were not significantly
different (P>0.05) among the treatments and rumen parameters and nitrogen retention
of cattle were similar (P>0.05) in different treatments, however, the rumen N-NH3 and
VFAs concentrations were higher at 3 h after feeding as compared to those before
feeding. The CH4 production (L/kg DMI) had a trend of gradual reduction from
CFO0, CFO1, CFO2 and CFO3 treatments, however this (L/kg DDM) gradually
decreased among the treatments (Prespectively, and the linear relationship between the CH4 emissions and CFO
supplementation being y= 51.7-1.59x (R2=0.836). It was concluded that a consistent
reduction of CH4 production (L/kg DDM) and no adverse effect on nutrient
digestibility and rumen environment was found when increasing the CFO from 0 to
3% in the in vitro and in vivo experiments of the crossbred cattle.
Key words: climate change, environment, feedstuffs, lipid, nutrition, ruminants