Physico-chemical analysis and nutrient retention of mixed-culture fungal fermented mango (<i>Mangifera indica</i>) kernel cake in cockerels

Abstract

The study was conducted to evaluate the efficacy of mixed-culture fungal fermented mango (Mangifera indica) kernel cake (MKC) as chicken feed ingredient. Four fungi namely Rhizopus oligosporus (Ro), Aspergillus niger (An), Rhizopus stolonifer (Rs) and Penicillium chrysogenum (Pc) were mixed as starter inoculums to ferment MKC. Eight treatments consisting of RoAn fermented MKC (T1), RoRs fermented MKC (T2), RoPc fermented MKC (T3), AnRs fermented MKC (T4), AnPc fermented MKC (T5), RsPc fermented MKC (T6), unfermented MKC (T7) and maize as control ingredient (T8) were used for nutrient retention trial. One hundred and eight cockerels were allotted for the treatments ingredients for 72 h using a completely randomized design. The birds were fed on the ingredients with a tubular instrument, while water was administered ad-libitum during the experimental period. The pH (3.50) of RoRs fermented MKC decreased significantly (p < 0.05) compared with unfermented MKC which had highest pH 5.13 at 168 h. Majority of the fermented MKC had higher (p < 0.05) titratable acidity (8.25 - 15.37 mg/100 g) compared with unfermented MKC (10.61 mg/100 g). Between 5.62 and 11.05% of MKC biomass was lost during fermentation which was higher (p < 0.05) at 168 h compared with unfermented MKC. Crude protein of the fermented MKC was significantly (p < 0.05) higher than the values of unfermented MKC, while crude protein of RsPc fermented MKC (21.93%) and RoRs (23.96%) fermented MKC were higher (p < 0.05) than other treatments. A great extent of the mixed-culture fermented MKC had higher (p < 0.05) total carbohydrate and glucose compared with unfermented MKC. Between 59 and 80 min were obtained as transit time for birds fed on the mixed-culture fungal fermented MKC. Most of the values were higher (p < 0.05) than 62 min obtained for the unfermented MKC (T7). Birds fed on RoAn fermented MKC (T1) had highest feed intake (28.34 g/day/bird), while those fed on RoRs fermented MKC (T2) had lowest feed intake (21.90 g/day/bird) but had higher (p < 0.05) nutrient retention (59.45%). The values of average nutrient retention of the mixed-culture fermented MKC were significantly (p < 0.05) higher than the values of unfermented MKC (39.72%), except for RsPc fermented MKC (T6) that had 38.56%. Ranking according to average nutrient retention (ANR) of the birds fed on the test ingredients is as follows: RoRs (T2) > RoPc (T3) > Maize (T8) > RoAn (T1) > AnPc (T5) > AnRs (T4) > RsPc (T6). The study indicates that mixed-culture fungal fermented MKC had significant (p > 0.05) increase in titratable acidity, crude protein, glucose and biomass loss with decreased pH. There was improvement in transit time and significant (p > 0.05) increase in nutrient retention of the fermented MKC compared with unfermented MKC. In conclusion, results of the fermented MKC were comparable with maize which makes it suitable as a potential feed ingredient in chicken’s diet.

Keywords: Unfermented mango kernel cake, fermented mango kernel cake, mixed-culture starter inoculum, transit time, nutrient retention

African Journal of Biotechnology Vol. 9(36), pp. 5887-5892, 6 September, 2010