Black Soldier Fly Meal and Oil: effects of novel feed sources on growth traits and welfare in fattening pigs

Insect-derived products, such as Black Soldier Fly Larvae Meal (BSFLM) and Oil (BSFO), are gaining attention as sustainable alternatives to traditional feed ingredients like soybean meal and fats/oils for pigs. Beyond their nutritional role, these non-conventional feed sources have been attributed nutraceutical properties that might favourably influence the intestinal microbiota. Due to the growing interest in the relationship between animal nutrition and behaviour through the gut-brain axis, this study aims to evaluate the effects of BSFLM and BSFO not only on growth performance but also on some welfare indicators, specifically behaviour and skin lesions, in finishing pigs. Seventy-two crossbred barrows (initial body weight, BW: 28 kg; 70 days old) were randomly assigned to three dietary treatments: BSFLM, BSFO, and control (CNTR). Diets were isonitrogenous and isoenergetic, with 5% of soybean meal replaced by BSFLM in the BSFLM group, and 2% of conventional fats substituted by BSFO in the BSFO group. Pigs were reared for 204 days, reaching a final BW of 160 kg at approximately nine months of age. Growth performance was evaluated, including average daily gain (ADG) and feed conversion ratio (FCR). Diurnal individual behaviour (7 AM-7 PM) was recorded over four days distributed throughout the trial and analysed using the scan sampling technique (10 s of observation every 10 min of video). Body and tail lesions were assessed at the end of the trial according to the Welfare Quality® protocol. Growth and behavioural data were analysed using ANOVA, with Dunnett’s tests as a post-hoc, while lesion scores were evaluated using the chi-square test. Significance was set at p<0.05. The BSFLM group exhibited significantly lower BW and higher FCR compared to the control group (p = 0.03), while the BSFO group showed intermediate values. General behaviour was unaffected by dietary treatment, as were body and tail lesion scores. Further investigations will aim to explore the potential effects of BSFLM and BSFO on the intestinal microbiota to better clarify the underlying mechanisms behind the observed outcomes. Research supported by EU grant n°J83C22000830005–AGRITECH research programme.