effects of saline water stress on in vitro and in situ ruminal degradation kinetics of soybean meal in sheep

The study was conducted to determine the soybean meal (sbm) fermentation and degradation kinetics using gas production (gp) and nylon bag techniques in sheep under saline water stress. eight rumen-cannulated iranian shaal rams that received different levels of saline water, including the control group (480), 4000, 8000, and 12000 mg/kg total dissolved solids (tds) were used. the results showed significant differences between the experimental treatments in terms of the amount of methane produced, total gp, dry mater (dm) and crude protein (cp) degradation and the relevant parameters (p<0.05). the treatment containing 12000 mg/kg tds had the highest gp at 48, 72, and 96 h of incubation times. short-chain fatty acids, digestible organic matter, metabolizable energy, and net energy for lactation of sbm significantly differ between treatments (p<0.05), with the lowest amount at the 4000 mg/kg salinity level. the lowest amount of methane emission was observed in the treatment containing 8000 and 12000 mg/kg tds. the results demonstrated that drinking water salinity significantly influenced the dm and cp degradability in sbm. the highest effective degradability values for dm and cp were observed in the treatment containing 12000 mg/kg tds. the highest values of b fraction for dm and cp were observed in the treatment containing 8000 mg/kg tds. also, slowly degradable protein and effective rumen degradable protein significantly (p<0.05) increased by increasing the salinity levels. in contrast, the undegradable protein, digestible undegradable protein and metabolizable protein were decreased with increasing water salinity. in conclusion, drinking water salinity affected the soybean meal fermentation and degradation kinetics and nutritional value. the treatment containing 12000 mg/kg tds in drinking water decreased methane production and metabolizable protein in sheep.