The efficacy of kenaf leaf meal on the apparent nutrient digestibility and physiological parameters of New Zealand white rabbit bucks

Abstract This study was conducted to assess the effect of gradually incorporating varying levels of kenaf leaf meal (KLM) on nutrient digestibility, feed intake, growth rate and blood biochemical indices of New Zealand white rabbit (NZWR) bucks. Twenty-eight (28) NZWR bucks (2.3 ± 0.47 kg, 98 days old) were raised on four isonitrogenous and isoenergetic diets formulated by partially replacing soyabean meal in a commercial rabbit diet at 0% (KLM0), 2.5% (KLM2.5), 5% (KLM5.0), and 7.5% (KLM7.5). There was a significant linear increase for crude protein (R2 = 0.56; P < 0.0001), iron (R2 = 0.67; P = 0.0004), copper (R2 = 0.57; P = 0.01), lysine (R2 = 0.52; P = 0.01), methionine (R2 = 0.49; P = 0.019) and Aspartic acid (R2 = 0.59; P = 0.01) digestibility in response to increased KLM levels. The analysis of repeated measures showed no significant effect of diet × week on weekly feed intake, weekly weight gain and weekly feed conversion ratio, whilst weekly body weight gain showed a positive linear trend in week 10. The blood biochemical showed both negative linear and quadratic trends. Total antioxidants and phenolics showed positive linear trends, whereas creatine and bilirubin showed positive quadratic trends. Therefore, it can be concluded that KLM can be gradually incorporated (up to 7.5%) into rabbit diets, partially replacing soyabean meal, and enhances nutrient digestibility, weekly weight gain and few blood biochemicals, without having detrimental effect on the overall growth parameters and most blood biochemical indices.