Effect of replacement of concentrate mixture with isonitrogenous leaf meal mixture on growth, nutrient utilization and rumen fermentation in goats

This study was conducted to examine the effect of replacing concentrate mixture with leaf meal mixture of Leucaena leucocephala–Melia azedarach–Morus alba in equal proportion on growth, nutrient utilization, blood and rumen metabolites in growing goats using completely randomized design. Twelve male non-descript goats were divided into two groups, control and experimental, consisting of six animals in each group. The control group was fed concentrate mixture whereas in experimental group 50% of concentrate mixture was replaced with isonitrogenous leaf meal mixture. The duration of experimental feeding was 45 days. Weekly body weights were recorded to assess growth rate of goats. After 30 days of experimental feeding a metabolism trial of 6 days duration was conducted to determine digestibility of nutrients and nitrogen, calcium and phosphorus balance. Blood samples were collected at 0, 7, 14, 21, 30 and 45 days of experimental feeding to study blood metabolites. Rumen liquor was also collected at 0 and 30 days to study rumen metabolites. The average daily gain (g) of control group (51.56) and experimental group (62.22) was statistically (P > 0.05) similar. The goat of control and experimental group had statistically (P > 0.05) similar intake (g/kgW0.75/day) of dry matter (60.70 vs 64.64), concentrate mixture (40.16 vs 41.60) and wheat straw (20.53 vs 23.05), respectively. The digestibility (%) of dry matter, organic matter, crude protein and ether extract was significantly (P < 0.05) depressed in experimental group of goat (65.60, 68.90, 65.62 and 63.05, respectively) as compared to control group (75.14, 77.41, 76.06 and 79.14, respectively). The digestibility (%) of neutral detergent fibre, acid detergent fibre and hemicellulose was similar in control (66.73, 65.49 and 64.97, respectively) and treatment group (58.21, 51.66 and 64.97, respectively). Animals of both the groups were in positive balance of nitrogen, calcium and phosphorus. Nitrogen balance (g/day) in control and treatment group of goat was similar (3.86 and 4.05, respectively) while calcium and phosphorus balance (g/day) was significantly (P < 0.05) higher in control group (2.34 and 1.02) than treatment group (1.06 and 0.22). There was no statistically significant (P > 0.05) effect of collection period and diet composition on the blood biochemical metabolites (hemoglobin, glucose, total protein, albumin, globulin and urea nitrogen) of goats. The pH of rumen fluid at 0 and 30 days of experimental feeding was 6.60, 6.60 for control group and 6.69, 6.33 for experimental group of goats. There was no significant difference (P > 0.05) in nitrogenous fractions (mg/dl) (ammonia nitrogen (19.27 vs 19.30), total nitrogen (101.52 vs 100.14), TCA-ppt nitrogen (50.24 vs 48.84) and non-protein nitrogen (50.06 vs 51.12) of rumen fluid collected at 30 days of experimental feeding of control and treatment group of goats, respectively.