Rumen Morphometry and Blood Metabolites in Bali Cattle: Effect of Feeding Native Grass and Palm Oil Sludge

The objective of this study was to examine the rumen morphometric characteristics and blood metabolites of Bali cattle fed diets based on native grass (100%, Treatment T1) and native grass supplemented with palm oil sludge (grass 60% and palm oil sludge 40%, Treatment T2). Twenty Bali cattle (males, average body weight 240,47 ±11,37 kg) were placed in communal pens with feeders and waterers. They were fed the experimental diets for 30 days, after which they were slaughtered, and rumen tissues from the ventral and dorsal regions were isolated for measurements of papillae height, width, and crypt depth. Blood samples were collected through the coccygeal vein using a syringe to measure triglycerides, blood glucose, and total protein. Total protein was measured using a photometric calorimetric test, and enzymatic colorimetric tests were conducted to analyze triglyceride and glucose. Observation and histological imaging of the rumen were conducted using microscopes equipped with digital cameras and computers. Histological measurements, including crypt length, width, depth, and total absorptive area, were carried out using ImageJ software. The blood triglycerides and total protein of cattle in treatment T2 were significantly higher than those fed diet T1(P<0.05). The glucose levels of cattle in all treatment groups were not significantly different (P>0.05). Feeding solely native grass resulted in thicker ventral and dorsal crypts, as well as the ratio of the depth of crypt and papillae height of the dorsal part of Bali cattle rumen(P<0.05). In conclusion, feeding native grass + Palm Oil Sludge leads to an increase in blood triglycerides and total protein. However, animals fed native grass (T1) showed a higher crypt depth in the ventral and dorsal rumen, increasing rumen crypt depth and papillae height ratio.