Nutrient digestibility of rabbits fed diets containing varying inclusion levels of acha offal supplemented with Maxigrain^® enzyme

Abstract

Conventional feed ingredients used in formulating feed most especially cereals and protein sources obtained from maize and soybean are scarce and expensive because they suffer stiff competition with channels in the food chain that commands higher priority and which can pay higher prices than the compound feed industry. Acha (Digitaria exilis) offal is one of the non-conventional feedstuffs and has been advocated to replace maize in the diet of rabbits. This study aimed at determining the nutrient digestibility of rabbits fed diets containing varying levels of Acha Offal (AO) supplemented with Maxigrain® enzymes. Forty eight (48) rabbits of mixed breeds and similar live weight (0.4-0.9kg) were used in two experiments consisting of weaner and grower phases which lasted 42 days each. Six treatments diets namely T1, T2, T3, T4, T5 and T6 were compounded to be isocaloric of 2700kcal/kg and iso-nitrogenous of (18% crude protein) for weaner phase while (15% crude protein) and isocaloric of 2500kcal/kg for grower phase. Each treatment was replicated 4 times with 2 rabbits each arranged in a 3x2 factorial fitted into Completely Randomized Design having AO (0, 15 and 30%) and enzyme (0 and 200ppm) as the main factors. Feed and water were provided to the rabbits daily and all standard routine management practices were strictly observed throughout the experiment. Similarly, at the end of the feeding trial of each phase, faecal samples were collected from two rabbits in each of the 6 units for proximate analyses. At weaner phase; Rabbits on 30% acha offal recorded higher digestibility of Crude Protein (CP) (75.55%) and Crude Fibre (CF) (30.73%) than those on 0 and 15% AO. There was significant (P<0.05) increased digestibility of Neutral Detergent Fibre (NDF) in 0% (21.58%) and 30% (21.33%) diets than 15%. Rabbits fed 15% (11.25%) and 30% (10.80%) AO diets showed improvement in the digestibility of Acid detergent Fibre (ADF) than on 0%. Diets supplemented with 200ppm enzyme recorded higher (P>0.05) digestibility of Nitrogen Free Extract (NFE) (36.50%) and acid detergent lignin (29.25%) but decreased CP (70.67%) and hemicellulose (36.67%) digestibility.T5 had significantly (P<0.05) higher CP (81.10%) and lower NFE (13.05%) than the rest of the treatments. During the growing phase; 0% AO showed significant (P<0.05) lower CF (28.69%) digestibility than 15(35.13%) and 30% (36.42%) diets. There was no significant (P>0.05) effect of enzyme between the diets in all the parameters measured except in NFE where 0ppm (37.05%) had significant (P<0.05) increased digestibility than 200ppm (36.73%) enzyme. There was significant (P<0.05) higher digestibility of nitrogen free extract in T3 (37.35%) although not significant (P>0.05) different from T1 and T2. However, T6 (36.58%) showed lower significant (P<0.05) digestibility of NFE and was not different (P>0.05) from T1, T4 and T5. Based on the results of this research; acha offal 30% and supplemented with 200ppm Maxigrain® enzyme in the diets of rabbits had no adverse effect in their ability to digest the nutrient therein.