The effects of partially replacing animal proteins with full fat black soldier fly larvae meal in nursery diets on growth performance and indices of immune system robustness of newly weaned pigs

Black soldier fly larvae meal (BSFLM) is enriched with both chitin and medium chain fatty acids (MCFA). Chitin acts as an immune stimulant and prebiotic to support a balanced and diverse population of gut microbes while MCFA exhibit anti-inflammatory and antimicrobial properties. This makes BSFLM a promising alternative to in-feed antibiotics in the diets of newly weaned pigs. One hundred and forty-four newly weaned pigs (6.73±0.39 kg initial BW; 21 days of age) were placed in 24 pens (6 pigs per pen) and randomly assigned to one of four dietary treatments (study d 0; n=6), which were fed over 3 phases (phases 1, 2, and 3 were fed for 7, 14, and 21d, respectively). Two nursery diets were formulated with 25% (LowFF) and 50% (HighFF) of animal protein sources replaced by full fat BSFLM and two commercial nursery diets were used as controls (-CON no antibiotics; +CON with 220mg Aureomycin per kg of complete feed). Individual pig BW and per pen feed disappearance were recorded weekly. On d 37, two pigs per pen underwent a delayed hypersensitivity test. Skin swelling was measured at 0, 6, 24, and 48hr post-intradermal injection with antigens OVA and CAA as indices of humoral and cell-mediated immune responses, respectively. Pigs fed the -CON had lower ADFI and G:F in phase 2 versus those fed +CON or the BSFLM diets (P<0.05 and P<0.05). Overall ADG, ADFI, G:F, and final BW (27.64±0.88 kg) were not affected by dietary treatments. Pigs fed the +CON, LowFF, and HighFF diets had a more robust immune response to OVA at 6hr than those fed the –CON diet (P=0.078, P<0.05, and P<0.05, respectively). Both inclusion levels of BSFLM in nursery diets supported growth performance, and indices of immune function not different from the +CON. Therefore, BSFLM may be a viable alternative to include in nursery diets as a replacement for infeed antibiotics. 

Key words: black soldier fly larvae meal, pig, antibiotics, immune system robustness.

Published in the proceedings of the Animal Nutrition Conference of Canada 2020. For information on the event, past and future editions, check out https://animalnutritionconference.ca/.