Black soldier fly (Hermetia illucens) larvae meal (HILM) is a promising alternative to soybean meal (SBM). However, little information is available on the effect of microwave-dried HILM as a dietary protein source in the diets of laying hens. We studied the effect of dietary inclusion level of microwave-dried HILM on productive performance, cecal volatile fatty acid profile, egg quality, overall fatty acid profile, and heavy metal residues of the egg in laying hens. A total of 144 laying hens (25-week-old) were randomly assigned to three dietary groups (eight replicates and six birds/cage): a control diet, and two experimental diets in which SBM was replaced with 2% HILM (2HILM) and 4% HILM (4HILM). The laying hens that fed the HILM showed satisfactory results in productive performance and egg quality. Branched-chain fatty acid levels increased linearly (p < 0.001) with dietary treatment in the cecal digesta. Total monounsaturated fatty acid increased linearly (p < 0.01), while total polyunsaturated fatty acid decreased linearly (p < 0.01) in the eggs by dietary treatments. Heavy metals, magnesium, zinc, and aluminum were increased linearly with dietary treatment; however, undesirable heavy metals were under permissible levels. Thus, microwave-dried HILM could be a possible alternative to SBM in the diets of laying hens; however, improvements in fatty acid profile are needed.

The present study investigated the optimum blending condition of protected fat, choline and yeast culture for lowering of rumen temperature. The Box Benken experimental design, a fractional factorial arrangement, and response surface methodology were employed. The optimum blending condition was determined using the rumen simulated in vitro fermentation. An additive formulated on the optimum condition contained 50% of protected fat, 25% of yeast culture, 5% of choline, 7% of organic zinc, 6.5% of cinnamon, and 6.5% of stevioside. The feed additive was supplemented at a rate of 0.1% of diet (orchard grass:concentrate, 3:7) and compared with a control which had no additive. The treatment resulted in lower volatile fatty acid (VFA) concentration and biogas than the control. To investigate the effect of the optimized additive and feed energy levels on rumen and rectal temperatures, four rumen cannulated Hanwoo (Korean native beef breed) steers were in a 4×4 Latin square design. Energy levels were varied to low and high by altering the ratio of forage to concentrate in diet: low energy (6:4) and high energy (4:6). The additive was added at a rate of 0.1% of the diet. The following parameters were measured; feed intake, rumen and rectal temperatures, ruminal pH and VFA concentration. This study was conducted in an environmentally controlled house with temperature set at 30°C and relative humidity levels of 70%. Steers were housed individually in raised crates to facilitate collection of urine and feces. The adaptation period was for 14 days, 2 days for sampling and 7 days for resting the animals. The additive significantly reduced both rumen (p<0.01) and rectal temperatures (p<0.001) without depressed feed intake. There were interactions (p<0.01) between energy level and additive on ruminal temperature. Neither additive nor energy level had an effect on total VFA concentration. The additive however, significantly increased (p<0.01) propionate and subsequently had lower acetate:propionate (A/P) ratios than non-additive supplementation. High concentrate diets had significantly lower pH. Interactions between energy and additive were observed (p<0.01) in ammonia nitrogen production. Supplementation of diets with the additive resulted in lower rumen and rectal temperatures, hence the additive showed promise in alleviating undesirable effects of heat stress in cattle.

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Here, the effect of microwave-dried black soldier fly (Hermetia illucens) larvae meal (HILM) as a dietary protein source on the growth performance and health of broilers was evaluated. A total of 126 male broilers were randomly allocated to three treatments (six replicates of seven birds per group): control diet (CON) of corn and soybean meal and two experimental diets in which soybean meal was replaced with 25% (25HILM) or 50% (50HILM) HILM. The broilers were slaughtered at 35 d to determine the apparent ileal digestibility (AID), volatile fatty acid (VFA) profiles, and length and weight of the small intestine. Blood samples were collected from 36 randomly selected birds (12 broilers per treatment) to determine serum parameters and haematological traits. Average daily gain, feed intake, and AID of protein were decreased (P<0.05) in the 50HILM group compared with those in the CON group. Dietary HILM increased (P<0.05) the relative length of the entire digestive tract and total VFAs in the caecal digesta. Serum low-density lipoprotein cholesterol was the lowest (P<0.01), but the triglyceride levels were the highest (P<0.05) in the 50HILM group. The serum phosphorus level was lower in both HILM diet-fed groups (P<0.01), whereas the creatine phosphokinase level was lower in the 50HILM group than in the CON group. In contrast, the 50HILM group showed higher (P<0.05) monocyte and red blood cell distribution width-standard deviation. In conclusion, dietary microwave-dried HILM positively influenced the VFA and cholesterol levels; however, growth performance was negatively affected by malnutrition caused by low protein digestibility in the 50HILM group. Microwave-dried HILM is a valuable ingredient for broiler diets, with up to 25% substitution showing no detrimental effects on growth performance and health. Further studies are needed to improve HILM digestibility.