A comparison of in vitro quality parameters and digestibility between locally produced and imported soya oilcake meal destined for the South African pig industry

Abstract

The processing of soya oilcake is important to ensure protein availability and high degradability of the soya proteins. Pig producers in South Africa are concerned about the quality of locally processed soya oilcakes and the effect that it may have on the intestinal health and lifetime production of the pig. The primary aim of this study was to compare the quality of locally processed soya oilcake to soya oilcake imported from Argentina. The trail consisted of two parts. In part one of the trail, eighty-eight samples of soya oilcakes from three different processing plants in South Africa and one from Argentina was analysed for their nutritive value and antinutritive factors. The results from the in vitro analyses were used to conduct the second part of this trail. Thirty-two piglets were divided into four treatment groups, the control group (diet containing no trypsin inhibitors), a low trypsin inhibitor group, a medium trypsin inhibitor group and a high trypsin inhibitor group. A digestibility trail was conducted to determine the effect of antinutritive factors on the digestibility of CP in pigs. The nutrient analyses suggested that the imported soya oilcake is of better quality than the locally produced product. All the results for the imported soya oilcakes were very consistent, with minor variations and had lower trypsin inhibitor activity. The results obtained from this study showed that some of the local soya oilcake processing plants in South Africa produced products of higher quality than others. One of the locally processed soya oilcakes, named soya oilcake 3 in this study, was identified as a good replacement for the imported soya oilcake. Soya oilcake 3 had a CP value of 53.11% which compared well with the imported soya oilcake with a similar CP value of 53.51%. The trypsin inhibitor concentration of the imported soya oilcake was the lowest and the second lowest in soya oilcake 3. Due to the high variance found in the results obtained from the in vivo digestibility study, it is not possible to make a conclusion on the effect of feeding lower quality soya oilcakes to weaner pigs. Further research is needed on the effect of trypsin inhibitor on gut health and digestibility of crude protein in weaner pigs.