Two experiments were conducted to determine standardized ileal digestibility (SID) of AA (Exp. 1) and net energy (Exp. 2) in two black soldier fly larvae meal (BSFLM) samples [full fat (FF; 42.5% CP, as-fed) and defatted (DF; 40.8% CP; as-fed)] for growing pigs. Two cornstarch-based diets were formulated with FF and DF BSFLM as the sole sources of AA. A nitrogen-free diet was also used and the corn starch:sucrose:oil ratio was kept constant among diets to calculate DE by difference method. In each Exp., pigs were fed 2.8 × estimated maintenance energy requirement. In Exp. 1, 8 ileal-cannulated barrows (25.1 ± 0.41 kg initial BW) were used in a replicated 2 × 2 Latin square design (n = 8). In each period, pigs were adapted to diets for 5 days followed by 2 days of continuous ileal digesta collection for 8 hours. The SID of AA were calculated using basal endogenous losses for pigs fed a nitrogen-free diet. In Exp. 2, 8 barrows (23.4 ± 0.54 kg initial BW) were used in a partially replicated Latin square design (n = 8). In each period, pigs were adapted to diets for 7 days, followed by 5 days of total urine collection and fecal grab sampling. The SID of CP (80.6 ± 1.1 %) and Lys (88.0 ± 1.4 %) were not different between FF and DF BSFLM. The SID of Arg, Val, Ala, and Pro tended to be less, and the SID of Met tended to be greater for the FF versus the DF BSFLM (P = 0.034, 0.090, 0.053, 0.065, 0.074, respectively). Digestible energy (4927 vs 3941± 75 kcal/kg), ME (4569 vs 3396 ± 102 kcal/kg), and predicted NE (3477 vs 2640 ± 30 kcal/kg, using equations from Noblet; 3479 vs 2287 ± 28 kcal/kg, using equations from Blok, respectively) were greater for the FF versus the DF BSFLM (P < 0.05). The apparent total tract digestibility of NDF and ADF were greater for the FF versus the DF BSFLM (P ≤ 0.05). Both FF and DF BSFLM had high SID for most AA, however, FF BSFLM was a better source of net energy for growing pigs. Therefore, both FF and DF BSFLM could be used as protein alternatives in growing pig diets.

One hundred and forty-four newly weaned pigs (6.74 ± 0.23 kg initial BW; 21 days of age) were used to determine the effect of partially replacing animal protein sources with black solider fly larvae meal (BSFLM) in nursery diets on growth performance, gut morphology, and immune response. After weaning, pigs were placed in 24 pens (6 pigs per pen) and pens were randomly assigned to one of four dietary treatments (study d 0; n = 6), which were fed over 3 phases (phases I, II, and III were fed for 7, 14, and 21 days, respectively). Two nursery diets were formulated with 25% (LowFF) and 50% (HighFF) of the animal protein sources replaced by full fat BSFLM. Conventional nursery diets including animal protein sources without (CON-) and with antibiotics (220 mg Aureomycin per kg of complete feed; CON+) served as controls. On day 8, two pigs per pen were sacrificed to collect organ weights and for intestinal histomorphological measurements. On days 9 and 23, two pigs per pen were vaccinated with the novel antigen ovalbumin (OVA). Blood samples were collected on days 9, 23, and 38 to assess concentrations of plasma haptoglobin and OVA-specific immunoglobulins G (IgG) and IgG1. On day 38, the same two pigs per pen underwent a dermal hypersensitivity test and skin-fold thickness was measured at 0, 6, 24, and 48 h post-intradermal injection with OVA. Pigs fed the CON- had greater ADFI and lower G:F in phase 2 versus those fed CON+ and HighFF diets (P < 0.05 and P < 0.05); intermediate ADFI was observed for pigs fed the LowFF diet. Overall in the nursery period, ADG (496 ± 13 g), ADFI (743 ± 23 g), G:F, and final BW (27.61 ± 0.66 kg) were not different among dietary treatments. There were no differences in organ weights, jejunal or ileal villus heights, or crypt depths among dietary treatments. There were no differences in OVA-specific IgG, IgG1, or plasma haptoglobin among dietary treatments at any of the blood sampling times. Although not different, pigs fed the LowFF, HighFF, and CON+ diets had respectively 2.0, 1.7, and 1.4× greater dermal hypersensitivity response to OVA versus those fed CON-. Both inclusion levels of BSFLM in nursery diets supported growth performance, gut morphology, and indices of immune function not different from the CON+, which suggest that full fat BSFLM can replace at least 50% of animal protein sources in nursery diets of pigs without any deleterious effects on pig growth.

Two experiments were conducted to determine the standardized ileal digestibility (SID) of AA (Exp. 1) and available energy (Exp. 2) in two black soldier fly larvae meal (BSFLM) sources [full fat (FF) and defatted (DF)] for growing pigs. Two corn starch-based diets were formulated with FF and DF BSFLM as the sole sources of AA. A nitrogen-free diet was also used and the corn starch:sucrose:oil ratio was kept constant among diets to calculate digestible energy. In Exp. 1, 8 ileal-cannulated barrows (25.1±0.41 kg initial BW) were used in a replicated 2 x 2 Latin square design (n = 8). In each period, pigs were adjusted to diets for 5d followed by 2d of continuous ileal digesta collection for 8 h. The SID of AA were calculated using basal endogenous losses for pigs fed a nitrogen-free diet. In Exp. 2, 8 barrows (23.4±0.54 kg initial BW) were used in a partially replicated Latin square design (n=8). In each period, pigs were adjusted to diets for 7d, followed by 5d of total urine and fecal grab sample collection, and 24hr in indirect calorimetry chambers to determine heat production. The SID of Arg, Val, Ala, and Pro tended to be less, and the SID of Met tended to be greater for the FF versus the DF BSFLM (P=0.034, 0.090, 0.053, 0.065, 0.074, respectively). Digestible, metabolizable, and net energy (4101 vs 3257±224 kcal/kg) were greater for the FF versus the DF BSFLM (P< 0.05). The ATTD of phosphorus, neutral detergent fiber, and acid detergent fiber were greater for the FF versus the DF BSFLM (P< 0.05). In conclusion, the SID AA in FF and DF BSFLM were high and similar to those of soybean meal. The FF BSFLM is a better source of available energy for growing pigs compared to DF BSFLM.