Effects of partial or complete replacement of soybean meal with commercial black soldier fly larvae (Hermetia illucens) meal on growth performance, cecal short chain fatty acids, and excreta metabolome of broiler chickens

Black soldier fly larvae meal (BSFLM) is receiving great attention as a rich source of protein and antimicrobials for poultry. Therefore, we evaluated the effects of partially or completely replacing soybean meal (SBM) with commercial BSFLM on growth performance, tibia traits, cecal short chain fatty acid (SCFA) concentrations, and excreta metabolomes in broiler chickens (Gallus gallus domesticus). A total of 480 day-old male Ross × Ross 708 chicks were assigned to 6 diets (8 replicates/diet): a basal corn-SBM diet with in-feed bacitracin methylene disalicylate (BMD), a corn-SBM diet without BMD (0% BSFLM), and four diets in which the SBM was substituted with 12.5, 25, 50, and 100% BSFLM. Body weight (BW), feed intake (FI) and cumulative feed conversion ratio (cFCR) were monitored on days 14, 28, and 35. Cecal SCFA levels were determined on days 14, 28, and 35. Tibia traits and excreta metabolomes were determined on day (d) 35. On d14, birds fed 12.5 and 25% BSFLM had a similar BW, FI, and cFCR as birds fed BMD (P > 0.05). On d 35, birds fed 12.5% BSFLM had a similar BW, FI and cFCR as birds fed BMD or 0% BSFLM (P > 0.05). For each phase, birds fed 100% BSFLM had a lower BW, FI and higher cFCR than birds fed BMD or 0% BSFLM (P < 0.05). On d 35, BW decreased linearly, quadratically, and cubically with increasing levels of BSFLM (P < 0.01). Overall (d 0-35), BSFLM linearly, quadratically, and cubically decreased FI and quadratically and cubically increased cFCR (P < 0.01). Quadratic responses were observed for tibia fresh weight (P = 0.049) and ash content (P = 0.022). BSFLM did not impact cecal SCFAs levels. The excreta metabolome of birds fed 100% BSFLM clustered independently from all other groups and exhibited greater levels of putatively identified methionine, lysine, valine, glutamine, histidine and lower levels of arginine as compared to all diets. Taken together, substitution of SBM with ≤25% of BSFLM in the starter phase may be used as an alternative to BMD.

The development of a semisynthetic diet deficient in methionine for adult cats for controlled feline nutrition studies: effects on acceptability, preference, and behavior responses

Chemically defined diets are commonly used in amino acid (AA) requirement studies to allow for tight control of AA delivery. However, those diets are not representative of commercial diets in the market and are unpalatable. Methionine (Met) is usually the first limiting AA in cat diets, but little is known about its requirement for adult cats. Thus, the objectives of this study were: 1) to develop a semisynthetic diet limiting in Met and evaluate its effect on acceptance and feeding behavior in cats; and 2) to evaluate the effect of different sources and inclusions of Met on preference in cats fed the semisynthetic diet. A semisynthetic diet deficient in Met and total sulfur AA (TSAA) was developed. Healthy adult male cats (n = 9) were fed (0800 and 1600 h) the semisynthetic diet top dressed with DL-Met solution (T-DLM), to meet 120% of the TSAA requirement, for 8 d. Feed intake was measured and a 30-min video recording was taken at the 0800 h feeding to evaluate feeding behavior of the cats. Following the acceptability trial, two bowl tests were performed where first choice was recorded and intake ratio was calculated as consumed food (A/A + B). Three combinations were tested: semisynthetic diet deficient in Met (T-BASAL) vs. T-DLM; T-BASAL vs. diet sufficient in Met provided 2-hydroxy-4-(methylthio)-butanoic acid (T-MHA); and T-DLM vs. T-MHA. Average feed intake remained high throughout the acceptability period (94.5% intake of total offered), but some cats decreased intake, resulting in a decrease in BW (≤2.5% of initial BW) over time (P < 0.05). Behaviors were similar among days (P > 0.05) with the exception of grooming the chest and body (P < 0.05). No preferences were observed towards a specific treatment (Met source and level) during the two-bowl tests (P > 0.05) and agreed with the cats expressing similar feeding behaviors during the preference tests (P > 0.05). In conclusion, a semisynthetic diet deficient in Met was successfully developed and can be used in studies to evaluate the effects of low protein and AA supplemented diets. Cats seem to show no preference for Met source and/or inclusion level in a semisynthetic diet application, which is of benefit for future studies aiming to determine the Met requirement in this species.

Evaluation of standardized ileal digestibility of amino acids and metabolic availability of methionine, using the indicator amino acid oxidation method, in black soldier fly larvae (Hermetia illucens) meal fed to growing pigs

Standardized ileal digestibility (SID, %) of crude protein (CP) and amino acid (AA) and the metabolic availability (MA) of Met using the indicator amino acid oxidation (IAAO) method, in partially defatted black soldier fly larvae (PD-BSFL) meal were determined in growing pigs in 2 experiments. The Met SID value was then compared numerically with the Met MA to understand how different SID is compared with its MA value. In Exp. 1, 6 ileal-cannulated barrows (initial body weight [BW] = 18.03 ± 0.34 kg) were used in a 2-period switch back design and fed either a nitrogen-free diet (NFD) or test diet, with PD-BSFL meal as the sole source of AA, over two 11-d experimental periods, at a feeding level of 2.8 × estimated maintenance digestible energy requirement. Barrows were adapted for 9-d to the diet, followed by continuous 8-h ileal digesta collection on day 10 and 11. Digesta were pooled per pig within period. The SID of CP and Met of PD-BSFL meal were 76.1 ± 6.2% and 90.4 ± 3.9%, respectively. In Exp. 2, 7 barrows (initial BW = 18.77 ± 0.69 kg) were used in a 7 × 7 Latin square design with L-[1-13C]-Phe as the indicator AA. Each pig was randomly assigned to 1 of 7 dietary treatments over seven 3-d experimental periods. Two diet types were studied including reference (crystalline AA) and PD-BSFL test diets, each supplying graded intakes of Met at 55, 65, and 75% of the estimated SID requirement (NRC, 2012). The MA of Met was determined by comparing the IAAO response between the reference and PD-BSFL test diet using the slope-ratio method. Linear regression determined a negative slope of the best fit line for both the reference and test diets (P < 0.05). The MA of Met in PD-BSFL meal was 53.3%, which is as expected lower than the SID value. While it is generally appreciated that MA will be less than SID, the use of SID is more practical. In cases where SID cannot explain physiological outcomes of feeding a novel ingredient, IAAO may provide additional insight into whether MA should be explored.

Complete replacement of soybean meal with black soldier fly larvae meal in feeding program for broiler chickens from placement through to 49 days of age reduced growth performance and altered organs morphology

Black soldier fly larvae meal (BSFLM) is characterized with good nutritional and functional attributes. However, there is limited data on inclusion of BSFLM in broiler chicken rations from placement through to market weight. Therefore, we examined growth and organ responses of partial to complete replacement of soybean meal (SBM) with BSFLM in a practical feeding program. A total of 1,152 d-old male Ross × Ross 708 chicks were allocated to 48 pens and assigned one of six diets (n = 8). The diets were: a basal corn-SBM diet (0%BSFLM), 4 diets in which SBM in 0%BSFLM was replaced with BSFLM at 12.5, 25, 50, and 100% and a final diet (0 + AGP) in which 0%BSFLM was treated with coccidiostat (70 mg Narasin/kg) and antibiotic (55 mg Bacitracin Methylene Disalicylate/kg). For energy fortification, soy oil was used for 0%BSFLM diets and black soldier fly oil in the other diets. Body weight, feed intake (FI), BW gain (BWG), and mortality-corrected feed conversion ratio (FCR) were reported. Organ weights were recorded on d 24 and 49. On d 10, birds fed diets 12.5, 25, and 0 + AGP had higher BWG than birds fed diets 0, 50, and 100 (P < 0.01), and birds fed diet 100 had lower BWG than birds fed diets 0 or 50 (P < 0.01). Birds fed diets 50 and 100 had lower BWG than birds fed all other diets on d 24 and 49 (P < 0.05). Overall (d 0-49), BSFLM linearly (P < 0.01) decreased BW, BWG, and FI and increased FCR and mortality. The overall BWG of 50 and 100% BSFLM birds was 92 and 81% of birds fed 0%BSFLM, repectively and coresponding overall FI was 96 and 90%. An increase in gizzard, small intestine, pancreas, and liver relative weights were observed with increasing BSFLM inclusion (P < 0.01). The data indicated that lower levels of BSFLM could provide some growth-promoting effects commensurate to antibiotics in the starter phase. However, replacing SBM with greater amounts (≥50) of BSFLM reduced growth and increased organ size.

Egg quality and laying performance of Julia laying hens fed with black soldier fly (Hermetia illucens) larvae meal as a long-term substitute for fish meal

The use of insects in animal feed appears to be an efficient approach that contributes to solving the environmental issues related to leftover disposal; however, it has not been approved in some countries due to concerns about pathogenic infections. This study aimed to evaluate the feasibility of long-term substitution of fish meal in poultry feed with organic defatted black soldier fly larvae (BSFL) meal prepared from BSFL raised on leftovers. The 87 Julia laying hens (178-day-old) were allotted in a completely randomized design with three treatments (29 layers in each treatment). The laying hens were fed maize grain and soybean meal-based diet containing either 3% fish meal, 1.5% fish meal and 1.5% BSFL meal, or 3% BSFL meal supplements for 52 wk (541-day-old). Results showed that substituting fish meal with BSFL meal had no effect on the laying rate, feed intake, and feed conversion ratio of laying hens, and only the complete replacement (3% BSFL meal) significantly increased the body weight of laying hens. In terms of egg quality, there was no significant effect on eggshell parameters (weight, thickness, and strength), albumen weight, yolk height, yolk color, and Haugh unit. However, both half (1.5% fish meal and 1.5% BSFL meal) and complete substitution of fish meal increased yolk weight (P < 0.01) and egg weight (P < 0.05). In conclusion, even if BSFL were fed leftovers and the meal was defatted with organic solvents, it can be used as a poultry feed ingredient without any adverse effect. Moreover, the complete substitution of fish meal with BSFL meal may be a feasible way to effectively contribute to the laying hens' performances and poultry farming costs. In addition to fish meal, the replacement of soybean meal with BSFL meal may also needs to be further studied for the extensive BSFL meal application in poultry feed.

The effects of partially replacing animal protein sources with full fat black soldier fly larvae meal (Hermetia illucens) in nursery diets on growth performance, gut morphology, and immune response of pigs

One hundred and forty-four newly weaned pigs (6.74 ± 0.23 kg initial BW; 21 d 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 (six pigs per pen) and pens were randomly assigned to one of four dietary treatments (study d 0; n = 6), which were fed over three phases (phases I, II, and III were fed for 7, 14, and 21 d, 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 d 8, two pigs per pen were sacrificed to collect organ weights and for intestinal histomorphological measurements. On d 9 and d 23, two pigs per pen were vaccinated with the novel antigen ovalbumin (OVA). Blood samples were collected on d 9, d 23, and d 38 to assess concentrations of plasma haptoglobin and OVA-specific immunoglobulins G (IgG) and IgG1. On d 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 postintradermal injection with OVA. Pigs fed the CON- had greater ADFI and lower G:F in phase II vs. 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.

Replacement of Fish Meal by Black Soldier Fly (Hermetia illucens) Larvae Meal: Effects on Growth, Haematology, and Skin Mucus Immunity of Nile Tilapia, Oreochromis niloticus

Simple Summary

Fish meal (FM) is the primary ingredient of the farmed fish’s diet. However, the decline in wild fish catches, and the growing demand for aquaculture feed have resulted in a dramatic reduction of FM supply. Thus, it is essential to seek for alternatives, such as insect meal (IM), to support sustainable aquafeed production. Among insects, the black soldier fly larvae are promising because they are rich in essential amino acids, minerals, and vitamins. Therefore, the present study was performed to assess the effects of IM as a partial or total replacement of FM on the growth and hematological parameters and skin mucus immunity of Nile tilapia. Growth and feed utilization efficiency indices, feed intake, survival rates, and hematological parameters were not significantly different between FM and IM fed fish, while the mucosal immune response was improved in IM fed fish. In conclusion, these results show that IM can be used to substitute FM in the Nile tilapia diet. These findings can be used to develop alternative aquafeed for sustainable aquaculture.

Abstract

Fish meal (FM) is no longer a sustainable source for the increasing aquaculture industry. Animal proteins from insects may be used as a FM alternative source as long as they do not create adverse effects in fish. Black soldier fly larvae meal (BSFLM) was tested in a 12-week experiment on Nile tilapia (Oreochromis niloticus). Four hundred and twenty (14.77 ± 2.09 g) fish were divided into seven groups and were fed seven diets: control (0% BSFLM-100% FM), and FM replaced by BSFLM at rates of 10%, 20%, 40%, 60%, 80% and 100%. Growth indexes, feed utilization efficiency indices, feed intake, and survival rate were not significantly different (p > 0.05) between FM and BSFLM fed fish. Values of red blood cell, white blood cells, hemoglobin, hematocrit, mean corpuscular volume and hemoglobin, mean corpuscular hemoglobin concentration, red blood cell distribution width, and platelet values were not affected by BSFLM. Skin, mucus lysozyme, and peroxidase activities were improved in BSFLM fed fish. BSFLM can be used as a substitution for FM in the Nile tilapia (O. niloticus) diet at up to a 100% rate with no adverse effects.

Standardized ileal digestible amino acids and net energy contents in full fat and defatted black soldier fly larvae meals (Hermetia illucens) fed to growing pigs

Two experiments were conducted to determine standardized ileal digestibility (SID) of amino acids (AA; Exp. 1) and net energy (Exp. 2) in two black soldier fly larvae meal (BSFLM) samples [full fat (FF; 42.5% crude protein (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 digestible energy (DE) by difference method. In each experiment, pigs were fed 2.8 × estimated maintenance energy requirement. In Exp. 1, eight ileal-cannulated barrows (25.1 ± 0.41 kg initial body weight) were used in a replicated 2 × 2 Latin square design (n = 8). In each period, pigs were adapted to diets for 5 d followed by 2 d 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, eight barrows [23.4 ± 0.54 kg initial body weight (BW)] were used in a partially replicated Latin square design (n = 8). In each period, pigs were adapted to diets for 7 d, followed by 5 d 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 (4,927 vs. 3,941 ± 75 kcal/kg), metabolizable energy (4,569 vs. 3,396 ± 102 kcal/kg), and predicted net energy (3,477 vs. 2,640 ± 30 kcal/kg, using equations from Noblet; 3,479 vs. 2,287 ± 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 neutral detergent fiber and acid detergent fiber 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.