Rumen fermentation characteristics, ciliate protozoa and utilization of nutrients in sheep fed sodium hydroxide treated mustard straw

Mustard straw (MS) was treated with sodium hydroxide (2% w/v) by soaking (6 hr) method. Malpura rams (8) were divided into 2 groups. One group (G1) wa s offered untreated MS (UMS) ad lib. along with concentrate (1% common salt ) @ 250 g/head/day, and group (G2) was offered treated MS (TMS) ad lib. alo ng with concentrate (without common salt) @ 250 g/head/day. Daily intakes o f DM and OM between groups did not differ significantly. However, rams in G Z. consumed 12% higher amount of straw. The rumen pH increased and TVFA (me q/dl SRL) decreased in G2 as compared to G1. However, the concentration (mg /dl SRL) of total-N, NH3-N and TCA-N was similar in G2 and G1. The populati on (x 10(4)/ml SRL) of spirotrichs was lower in G1 than that in G2 while of holotrichs higher in G1 than that in G2. Digestibility coefficients of DM, OM, NDF: ADF and cellulose were higher in G2 than that in G1 and the respe ctive means were 45.8 and 52.9, 51.3 and 58, 38.1 and 47, 31.4 and 39.6 and 36.8 and 54.0. However, CP, hemicellulose and gross energy digestibility d id not show much variation. Rams in both the groups were on positive N bala nce and N retention (% of N intake) was 37.7 and 47.1 in G1 and G2 respecti vely. The DCP (%) of the ration was higher in G1 (7.0) than that in G2 (5.6 ), whereas DE (Mcal/kg) of the ration did not differ significantly in G1 (2 .4) and G2 (2.5). It is concluded that on feeding of sodium hydroxide treat ed mustard straw-based ration, the number of holotrichs protozoa decreased while spirotrichs increased in the rumen of sheep. The soaking of mustard s traw in 2% sodium hydroxide solution for 6 hr improved its palatability and digestibility and thus feeding value.