Cassava root peel as a replacement for maize in diets for growing pigs: effects on energy and nutrient digestibility, performance and carcass characteristics

Two experiments were conducted to evaluate cassava root peel (CRP) as diet component for fattening pigs. In the first experiment, ten male pigs were used to investigate the nutrient digestibility and the nutritive value of CRP as replacement for maize in the diet at 0 %, 30 %, 40 %, 50 % and 60 %, while supplementing free amino acids (fAA). During two experimental periods, faeces were quantitatively collected and analysed for chemical composition. In the second experiment, 40 pigs received the same diets as in Experiment 1, and daily feed intake and weekly weight changes were recorded. Four pigs per diet were slaughtered at 70 kg body weight to evaluate carcass traits. Digestibility of dry and organic matter, crude protein, acid detergent fibre and gross energy were depressed (p0.05) at 60 % CRP; digestible energy content (MJ kg^(−1) DM) was 15.4 at 0 % CRP and 12.7 at 60 % CRP. In the second experiment, CRP inclusion had only a small impact on feed intake, weight gain and feed conversion ratio (p0.05) as well as on the length of the small intestine and the Longissimus dorsi muscle area. The missing correlation of daily weight gain and feed-to-gain ratio up to a CRP inclusion of 40 % indicates that negative effects of CRP on pig growth can be avoided by respecting upper feeding limits. Hence, a combined use of CRP and fAA can reduce feeding costs for small-scale pig farmers in countries where this crop-by product is available in large amounts

Feed value of enzyme supplemented cassava leaf meal and shrimp meal in pigs

Ten crossbred male pigs of 49.3±3.97 kg body weight were used to evaluate the digestibility, energy value and N (nitrogen) retention of two unconventional protein sources, i.e. cassava leaf meal (CLM) and shrimp meal (SM), with or without the addition of a nonstarch polysaccharide (NSP) enzyme complex (β-glucanase and xylanase). During two trial periods, each lasting 7 days, two pigs each were fed the following five experimental diets: Basal diet (BD), BD+cassava leaf meal with (CLM+E) and without enzyme addition (CLM) and BD+shrimp meal with (SM+E) and without enzyme (SM) supplementation.Total tract digestibility of Dry matter (DM) was general depressed in pigs fed diets containing the alternate protein sources. Crude protein (CP) and Gross energy (GE) digestibility were depressed in pigs fed cassava leaf meal (CLM) diet. Enzyme supplementation did not improve the digestibility of the energy and other proximate constituents. Faecal N output increased in pigs fed the alternate protein sources while Urine N and N retention were not affected (P>0.05) by the use of the alternate protein sources in the diets of pigs. There was reduced (P<0.05) conversion to ME in pigs fed diets containing the alternate protein sources. The ratio of DE/GE was lower in pigs fed diets containing CLM as compared to the basal diet. The digestibility energy values obtained for CLM, CLM+E, SM and SM+E were 10.2, 8.8, 10.1 and 10.0 MJ/kg DM respectively. Corresponding metabolizable energy were 9.8, 8.3, 9.0 and 9.3 MJ/kg DM, respectively. It was concluded that SM and CLM can be use individually be use in feeding growing pigs as partial substitute for the more expensive conventional plant protein feedstuffs, such as soybean; and can replace up to 23% of the diet of growing pigs.Keywords: Cassava leaf meal, shrimp meal, digestibility, N-retention, pig