Reducing hydrogen cyanide in cassava based diets to improve grower pig performance in Kenya

Abstract

In Kenya, the benefits of pig farming help many households; however, its growth is constrained by the high cost of commercial pig feeds, mainly caused by the constant dependence on maize. Cassava has been identified as a substitute for maize in feeds, however, its elevated levels of crude fibre and the hydrogen cyanide (HCN) contribute to poor nutrient digestibility in animals. This study evaluated the effect of Fermentation and Enzyme Treatment on the nutritional composition, in-vitro digestibility, cyanide reduction of Cassava (Manihot Esculenta) based diets (In a ratio of 1: 0.3; Root: 1; Leaf: 0.3, CRLM), and its impact on grower pig performance. In the first experiment, CRLM was subjected to five treatments: untreated (T1), fermented with Aspergillus niger (T2), spontaneously fermented (T3), enzyme-treated with Natuzyme® (T4), and fermented with Lactobacillus brevis (T5). Nutritional composition, digestibility, were analyzed. What the data reveals is that the optimal treatment was reconfirmed in the following feeding trials. In experiments two and three, 18 Landrace x Large White crosses (20 +/- 3 kg) were allotted three diets; 0% fermented CRLM (T1), 20% FCRLM (T2) and 40% FCRLM (T3). These diets were evaluated for their impact on growth performance, carcass traits and sensory characteristics of the pork. The in-vitro digestibility data, feeding trials and carcass data were all two-way analysed using the ANOVA procedures available in the Statistical Analysis System (SAS, 2023). Differences between means were subjected to Tukey’s test for significance at p < 0.05. In the clinical trial results obtained from the pretreatment phase, it was inconclusive that during the course of spontaneous fermentation (T3) the CRLM quality was improved by the decrease of HCN concentration from 45.00 ppm to 8.00 ppm and CF from 5.16% to 3.87%, and increase in crude protein from 7.47% to 11.09% and dry matter digestibility from 93.67% to 98.62%. The trial results indicated that the feeding of 20% of fermented CRLM resulted in the optimal average daily gain of 0.68 kg/day and the best feed conversion ratio of 4.16, with no detrimental effects on carcass traits and meat quality. These results indicated that spontaneous fermentation substantially increases the nutritive value of CRLM and as such, its use as a feed ingredient for pigs is safe and nutritionally adequate. Incorporating up to 20% FCRLM in grower pig diets can reduce feed costs while maintaining growth performance and pork quality.