Effects of Dietary Urea-Treated Maize Husk and Pelleting on Growth Performance, Reproduction, Blood Profile, and Carcass Characteristics of Female Rabbits (Oryctolagus cuniculus).

Abstract

Thirty-two (32) crossbred (Chinchilla × New Zealand White) weaner rabbits, all female, of averagely 8 weeks old with mean body weight of 950.7 g were used to investigate the effects of dietary urea-treated maize husk meal and pelleting on growth performances, reproduction, blood profile, and carcass characteristics. The rabbits were randomly assigned to eight dietary treatments with four rabbits per each treatment using a 2 × 4 factorial in a randomized complete block design (RCBD) for four months. Factor one was feed form with two levels: Pelleted and Non-pelleted, and factor two was Urea with four levels: 0 %, 2 %, 4 %, and 6 %. Sun-dried maize husks were treated with four levels of urea: 0 % (no urea), 2 %, 4 %, and 6 %. The respective treated maize husks obtained were used to formulate the experimental diet designated as PU0 % (0 % urea pelleted), NPU0 % (0 % urea non-pelleted), PU2 % (2 % urea pelleted), NPU2 % (2 % urea non-pelleted), PU4 % (4 % urea pelleted), NPU 4% (4 % urea non-pelleted), PU6 % (6 % urea pelleted) and NPU6 % (6 % urea non-pelleted). The data collected were subjected to a two-way analysis of variance (ANOVA) using Statistix Analytical Software Package version 10.0, (2024) and means were separated by using the Tukey’s least significant difference at 5 % probability level. The results showed that animals that were fed with the pelleted feed form significantly recorded higher (p = 0.045) total feed intake (9095±114.5 g) higher (p = 0.000) total weight gain (2226±30.32 g) and lower (p = 0.000) average feed conversion ratio (4.000±0.069). The interactions between 0 % urea level and pelleted feed form significantly recorded the highest (p = 0.014) total feed intake (9397±229.0). However, the interaction between 4 % urea level and pelleted feed form recorded the lowest (p = 0.118) average feed conversion ratio of (3.718±0.137) which indicates efficient feed utilization and better feed quality though, not statistically significant. Feed form and urea levels had no significant effect on gestation length (p = 0.729) and liveability of bunnies (p = 0.842). Again, non-pelleted feed form significantly had higher (p = 0.008) effect on litter size with value (5.750±0.537), litter weight, 238.2±16.27 g (p = 0.025) and weaning weight, 3355±217.2 g (p = 0.033). Non-pelleted feed form significantly (p < 0.05) recorded the higher white blood cells, haematocrit, granulocyte, haemoglobin, and lymphocyte, counts, serum urea, Alkaline Phosphatase Aspartate Aminotransferase and low-density lipoprotein against the pelleted. Total serum cholesterol was significantly higher (p = 0.001) with the non-pelleted feed form, (2.804±0.138 mmol/L) as a result of the significant higher (p = 0.000) low-density lipoprotein (1.508±0.107 mmol/L). There was a trend of significant increase in low-density lipoprotein with increasing urea levels with 6 % recording the highest (p = 0.008) value of (1.417±0.152 mmol/L). Increasing urea levels significantly (p = 0.000) tended to decrease caecal pH. There was a trend of significant (p = 0.018) increase percentage of visceral content (VC %) with increasing urea levels, with 6 % recording the highest value of (10.65±0.343 %). The results suggest that maize husk could be incorporated into rabbits’ diet either treated with 4 % urea level, or untreated without any detrimental effect on growth and reproduction. Urea-treated maize husk meal can be fed to rabbits in the non-pelleted form, and it is likely to increase reproductive performances such as litter size, livability percentage, litter size at weaning, and weaning weight.