This study aimed to evaluate the effects of the replacement of rice bran oil (RBO) with black soldier fly larvae oil (BSFLO) on growth performance, blood biochemicals, carcass quality, and metabolomics profile of breast muscle of Thai native chickens. A total of 192 1-day-old, mixed-sex, Pradu Hang Dam (Mor Kor 55) chickens were randomly allocated to one of three dietary groups. Each treatment had four replicates with 16 chicks per replicate (8 males and 8 females). Three dietary treatments were used: (T1) the control group, based on a corn–soybean meal with RBO, and two treatment groups that replaced 50% (T2) and 75% (T3) of RBO in the basal diet with BSFLO, respectively. Results showed that BSFLO inclusion at 50% and 75% did not adversely affect the productive performance of Thai native chickens (p > 0.05). Regarding blood profiles, on day 28, chickens fed 75% BSFLO exhibited significant increases in hemoglobin, hematocrit, and MCHC (mean corpuscular hemoglobin concentration) with lower eosinophil percentages compared to the control group (p < 0.05). Additionally, BSFLO supplementation raised glucose levels but decreased globulin and total protein levels (p < 0.05). On day 63, BSFLO inclusion primarily affected MCV (mean corpuscular volume), with higher values in the 50% BSFLO group (p < 0.05). It also increased globulin and HDL (high-density lipoprotein) levels while lowering AST (aspartate transaminase) concentrations (p < 0.05). For carcass and meat quality, BSFLO supplementation did not affect dressing percentage or edible meat yield (p > 0.05). However, it influenced meat pH and shear force (p < 0.05), with a higher pH at 24 h post-mortem in BSFLO-fed chickens. Metabolomics showed that arginine biosynthesis; phenylalanine, tyrosine, and tryptophan metabolism; alanine, aspartate, and glutamate metabolism; arginine and proline metabolism; and taurine and hypotaurine metabolism were the most differentially abundant. These findings suggest that BSFLO can be used for a partial replacement (50 to 75%) for RBO in Thai native chicken diets, potentially offering benefits for animal health and meat quality without compromising growth performance.

This study evaluated the effects of citric acid by-product (CABP), either alone or in combination with fibrolytic enzyme (F) and Lactobacillus spp. (L), in broiler diets. A total of 160 one-day-old male Arbor Acres broiler chicks (average initial body weight 43.0 ± 0.16 g) were randomly assigned to four CABP-based diets (4 replicates × 10 birds each): 12% CABP, CABP+F (0.05%), CABP+L (0.025%), and CABP+FL (0.05% F + 0.025% L). Birds were fed for 35 days in three phases: starter (days 1–10), grower (days 11–24), and finisher (days 25–35). Compared with the CABP-only group, broilers receiving CABP+F, CABP+L, or CABP+FL exhibited higher body weight and weight gain during the finisher and overall phases (p < 0.05). Carcass traits did not differ significantly among treatments, although meat hardness was reduced in the CABP+FL group (p < 0.05). Additive-supplemented groups also showed changes in intestinal morphology, with a lower villus height-to-crypt depth ratio compared with CABP alone. Red blood cell counts were not different between CABP and CABP+L, while hepatic enzyme activities (ALT, AST, ALP) remained unchanged across treatments, indicating no adverse effects on liver function. Overall, supplementation of CABP-based diets with fibrolytic enzymes and/or Lactobacillus spp. improved broiler performance and certain meat quality traits relative to CABP alone, without negative impacts on liver health or carcass yield. However, as no conventional corn–soy control diet was included, the results should be interpreted as comparisons within CABP-based diets.