Microbial conversion and biovalorization of fermented cassava waste biomass into livestock-based diets

Thirty weanling male Large White pigs of 13.46 ± 0.38 kg live weight were randomly allotted to five dietary treatments designated as T1 (the control diet), T2 (naturally fermented cassava starch residue [NFR] diet), T3 (microbe-fermented cassava starch residue [MFR] diet), T4 (naturally fermented cassava peel [NFP] diet) and T5 (microbe-fermented cassava peel [MFP] diet) as control and 40% inclusion of NFR, MFR, NFP and MFP, respectively, in a trial that lasted 168 days. The scrotal traits investigated were the right and left scrotal length (RSL and LSL), average scrotal length (ASL), right and left scrotal diameter, combined scrotal diameter (CSD) and combined scrotal circumference (CSC). The results revealed a progressive increase in body weight across treatments and a growth spurt observed within 112–140 days preceded by a period of rapid increase in all the scrotal traits. The combined scrotal circumference increased from 16.60 ± 0.62 cm at 56 days of age to 44.64 ± 0.87 cm at 224 days of age. Increase in scrotal length was preceded by increase in scrotal circumference which triggered the onset of puberty. In conclusion, CTW diets at 40% inclusion would not adversely affect body weight change but may affect scrotal traits morphometry especially the combined scrotal circumference. The inclusion of the microbial converted 40% MFR into diets of pre-pubertal boars could depress their breeding capacity. The scrotal traits in young male pigs could be used to predict body weight and the age of attainment of puberty. Graphical abstract