BackgroundThe study aimed to determine the apparent total tract digestibility coefficients (ATTDC) of nutrients, the apparent metabolizable energy (AME and AMEn) and the amino acid (AA) apparent ileal digestibility coefficients (AIDC) of a partially defatted (BSFp) and a highly defatted (BSFh) black soldier fly larvae meal. The experimental diets were: a basal diet and two diets prepared by substituting 250 g/kg (w/w) of the basal diet with BSFp or BSFh, respectively.ResultsSignificant differences were found between BSFp and BSFh meals for ATTDC of the nutrients: BSFp resulted more digestible than BSFh, except for ATTDC of CP which did not differed between meals, while a statistical trend was observed for ATTDC of DM and EE. The AME and AMEn values were significantly (P < 0.05) different between the two BSF meals, with higher levels for BSFp (16.25 and 14.87 MJ/kg DM, respectively). The AIDC of the AA in BSFp ranged from 0.44 to 0.92, while in BSFh they ranged from 0.45 to 0.99. No significant differences were observed for the AA digestibility (0.77 and 0.80 for BSFp and BSFh, respectively), except for glutamic acid, proline and serine that were more digestible in the BSFh meal (P < 0.05).ConclusionsDefatted BSF meals can be considered as an excellent source of AME and digestible AA for broilers with a better efficient nutrient digestion. These considerations suggested the effective utilization of defatted BSF larvae meal in poultry feed formulation.

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The aim of the present research was to determine the effect of low protein diets on growth performance, carcass traits and ammonia emission from barrows and gilts during the growing and finishing periods. For each period, three diets were formulated. A control diet (C) with 160 and 155 g crude protein (CP)/kg for the growing and finishing, respectively, a medium level diet (M) and a low level diet (L) with 10 and 20 g CP/kg less than the C, respectively. All the diets were supplemented with crystalline amino acids on an ideal protein basis. Barrows (90) and gilts (90) were sorted by bodyweight and sex and housed in three identical manually ventilated chambers. No significant effects of diet on pig performance were observed. In the finishing period, barrows were heavier (P < 0.001) and had higher average daily gain (P < 0.01) and average daily feed intake (P < 0.01) than gilts. Pigs fed the L diet had higher backfat thickness than those fed the other diets in the growing period (P < 0.05). Backfat thickness was higher (P < 0.01) in barrows than in gilts. Muscle depth decreased in pigs fed the L diet in the finishing period. Muscle depth was not affected (P > 0.05) by sex. Average ammonia emissions during the last 6 days were 117.7, 94.2 and 85.5 mg ammonia/kg pig.day for pigs fed the C, M and L diets, respectively. The results show that a reduction in dietary CP of 10 g/kg, accompanied by supplementation with crystalline amino acid reduced ammonia emission by 19.9% with no detrimental effects on growth performance and carcass characteristics, and a reduction of 20 g/kg reduced ammonia emission by 27.3% with no detrimental effects on growth performance but reduced muscle depth at slaughter.

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