A study of in vitro and in vivo greenhouse gas emissions, digestion, rumen environment and nitrogen retention of growing crossbred cattle supplemented by Catfish oil

Abstract

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 (P<0.05) among the treatments and they were gradually abated (P<0.05) when 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 (P<0.05) with the values of 51.3, 50.1, 49.8 and 46.1, respectively, 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.