Abstract:
Livestock production is one of the major sources of income in Rwanda. Pigs are among preferred livestock due to their short generation interval and small space requirement. Feeds account for 65-70% of total production costs in pig rearing, which invariably affects profit margins. Therefore search for alternative feedstuffs that are locally available and affordable like brewers’ spent grains (BSG) can be used to feed pigs and reduce the cost of production. BSG is the first solid material by-product that remains after barley grain has been fermented during the beer making process. This study evaluated the nutrient composition, effect and economics of substituting sow and weaner meal (SWM) with BSG on the performance of growing pigs in Rwanda. A feeding trial was conducted using 30 gilts of Landrace x Pietrain cross weighing 30 - 40±5kg. A completely randomized design (CRD) was used in which pigs were randomly allocated to 10 pens based on initial weight with 3 pigs per pen. Five treatments of BSG replacing SWM at a rate of 0% (T1), 25% (T2), 50% (T3), 75% (T4) and 100% (T5) were randomly assigned to pigs for 42 days. Weekly data on average daily feed intake (ADFI), average daily gain (ADG), feed conversion ratio (FCR) and net returns (based on the variable costs of production) was collected. Proximate analysis showed that nutrient composition of BSG and SWM differed significantly (P<0.05). BSG was higher in crude protein (CP) and crude fibre (CF) but lower in metabolizable energy (ME) compared to SWM. ADFI significantly increased from T1 to T3 and then decreased to T5 (P<0.05). Diet T3 had higher ADFI (4.14kg/pig/day) compared to T1 (2.31kg/pig/day) probably due to the high moisture content of BSG. The ADG was significantly different (P<0.05) among diets, but T1-T3 were similar (P>0.05) whereas T2 had higher ADG. Diet T5 resulted in loss of body weight of -0.153kg/pig/day probably due to the high CF and low dry matter in BSG. FCR was not different (P>0.05) in T1-T3 but significantly (P<0.05) different in T4 and T5. Feed cost decreased with the increase in BSG levels. The net return was higher in T3 (50% BSG) and lowest in T5. Based on the results of this study, it can be concluded that BSG can replace up to 50% SWM in grower pigs’ diets without adverse effect on daily gain and with some savings in feed costs.
