Ensiled slaughter offal as a protein source for growing pig

Authors

• Kirsi Partanen Department of Animal Science, P.O. Box 28, SF-00014 University of Helsinki, Finland
• Timo Alaviuhkola Agricultural Research Centre of Finland, Swine Research Station, SF-05840 Hyvinkää, Finland
• Matti Näsi Department of Animal Science, P.O. Box 28, SF-00014 University of Helsinki, Finland

DOI: https://doi.org/10.23986/afsci.72467

Abstract

The present study was conducted in order to evaluate the use of slaughter offal preserved by lactic acid fermentation in pig diets. Offal was first ground, autoclaved, and mixed with 70 kg sugar beet molasses per 1000 kg. After that it was inoculated with 2x105 lactic acidbacteria/g and incubated at 35°C for three days. The final pH ofthe fermented product was 3.80. The ensiled slaughter offal (ESO) contained 239 g dry matter (DM)/kg. and 319 g crude protein (CP) and 403 g crude fat (CF)/kg DM. CP contained 47 g lysine, 33 g threonine, 16 g methionine, and 8 g cystine/kg. A digestibility and nitrogen (N) balance assay was conducted with eight barrows using a 2x4 factorial arrangement in a 8x4 cyclic change-over design. The factors were protein source and protein level. Barley-based diets were supplemented with increasing levels (0, 20,40, and 60 g CP/kg) of ESO or soyabean meal (SBM). Increasing the protein supply led to a linear increase in the digestibility of CP (p<0.001) and a quadratic increase in the digestibility of CF (p<0.001). The apparent digestibility of organic matter, CP, and CF calculated by the regression method was 0.811, 0.898, and 0.789 for ESO and 0.849, 0.867, and 0.731 for SBM, respectively. N retention increased linearly with increasing protein supply (p<0.001), but no significant differences were observed between protein sources. Although the amount of N excreted in urine was higher (p<0.05) for ESO- than SBM- supplemented diets, there were no significant differences in urea-N excretion between protein sources. The daily weight gain increased linearly with increasing protein supplementation (p<0.001) and was higher for SBM- than for ESO-supplemented diets (p<0.05). A growth trial was conducted with 216 pigs using a randomized complete block design. No significant differences were observed in growth performance, feed consumption, or feed conversion rate between the control diet and the test diet. ESO provided 0.20 of DM and 0.22 of feed units of the test diet. Carcass weight and thickness of both back and side fat were similar on both treatments (p>0.05), whereas dressing percentage was higher in pigs fed thetest diet (p<0.01). No significant differences were found in the chemical composition or organoleptic scores of the longissimus dorsi muscle between the treatments.