EFFECT OF USING GUAVA LEAVES IN RUMINANT RATION ON RUMINAL FERMENTATION CHARACTERISTICS, METHANE EMISSION AND NUTRIENTS DIGESTIBILITY

Abstract

Guava leaves (GL) are sustainable and locally accessible forage in Egypt, which can serve as a valuable ingredient to ruminants’ diets, due to their rich nutritional value and secondary metabolites. The present study was carried out to evaluate the effect of partial/total substitution of corn silage by GL at 0%, 25%, 50%, 75% and 100% on rumen fermentation profile and nutrient degradability, as well as methane emission in vitro using a semi-automatic system of gas production assay. The findings showed that when GL accounted for 25% and 50% of the total mixed diet, volatile fatty acids dramatically decreased. Additionally, there was a very noticeable drop in methane generation as GL increased, particularly at 75% and 100% levels. Furthermore, throughout all recorded fermentation intervals, the diet containing 100% GL produced the least amount of gas. The current study indicated that the partitioning factor as an index of microbial protein synthesis varied significantly between 0% and 100% of GL, ranging from 3.7 to 4.9. Guava leaf inclusion has a negative impact (P<0.05) on the protozoa count, while the rumen pH rises noticeably when GL in the diet increases. The results in the current study concluded that the optimal level for replacing corn silage with GL should not exceed 25% in the TMR of ruminants.