ABSTRACT

The utilization of feed can be affected by the ingredients uesd, processing methods, management and gut microbiota. The growth and nutrient utilization could  negatively be affected by deleterious flora like mycotoxins which comes in different forms like ochratoxin, fumosin, and aflotoxin. Some supplements like bentonite has chelating effects on deleterious microbiomes communities. Consequently this research was designed to investigate the effects of bentonite as feed additives for African catfish C.gariepinus. The research also investigated the effects on the growth performances, feed utilization, gut morphology, gut microbial communities and culture water quality of C. gariepinus. To this effect five types of feed were made to vary in composition of bentonite supplements as follows; Feed 1, F1, (35g), Feed F2 (25g), Feed 3 F3(15g),Feed 4,F4( 5g)  Feed 5 F5( 0g).The feeds also contains significantly (P<0.05) similar quantities of soyabean meal and fish meal. The basal ingredients comprised of similar quantities of cassava and corn starch blend as binder. Specific quantities of the ingredients were weighed, mixed, pelleted and dried. The feed were used in feeding C. gariepinus of average weight 8-10g stocked at 15 fish per crate for 140days.  The results showed that bentonite enhanced feed conversion ratio (FCR), There is a significant different between the FCR of F1 (F1 1.63±0.15) and F5, (F5 2.70±0.11), (P<0.05), weight gain was highest (F1, 52.22±3.65) and F5 (30.91±0.86). Protein efficiency ratio was also significant difference between (F1 1.19±0.10) and F5 (0.57±0.02). The gonadal weight were also significantly higher for catfish fed with F1 (1.49±0.13), followed by those fed with F5 (0.54±0.14). The rate of gut evacuation was reduced by high inclusion of bentonite thus, enhancing proper breakdown and absorption of nutrients. There was positive correlation between increasing inclusion levels of bentonite and feed utilization, growth performances and gonadal developments. Gut microbiota were also improved by bentonite and positively correlated with increasing of bentonite. The results suggest that bentonite optimal inclusion level is (34%). These seem to follow the concept that African catfish is geophargic in nature, bentonite at 34% is recommended for farmers, because results suggest that bentonite supplement is a beneficial additive in catfish diet.