This experiment was conducted to evaluate the effects of bile acids (BAs) on the growth performance and lipid metabolism of broilers fed with different energy level diets. 480 one-day-old Arbor Acres broilers (45.01 ± 0.26 g) were allotted to a 2 × 2 factorial design with 2 levels of energy (basal or high-energy level) and 2 levels of BAs (with or without BAs supplementation), resulting in 4 groups of 8 replicates; the experiment lasted 42 d. High-energy diets decreased the feed/gain ratio (F/G) from 1 to 21 d (P < 0.05), and increased the liver index and abdominal fat percentage at 42 d (P < 0.05). The serum total triglyceride (TG) and high-density lipoprotein cholesterol at 42 d were increased by high-energy diets (P < 0.05), while the hepatic lipoprotein lipase (LPL) activity at 21 and 42 d was decreased (P < 0.05). BAs supplementation increased the body weight at 21 d and decreased the F/G during entire period (P < 0.05), as well as improved the carcass quality reflected by decreased abdominal fat percentage at 42 d and increased breast muscle percentage at 21 and 42 d (P < 0.05). The serum TG at 21 and 42 d were decreased by BAs (P < 0.05), and the hepatic LPL activity at 42 d was increased (P < 0.05). In addition, high-energy diets increased the expression of sterol regulatory element binding transcription factor 1, acetyl-CoA carboxylase, and fatty acid synthase (P < 0.05), while BAs diets decreased these genes expression (P < 0.05). Moreover, BAs supplementation also increased the expression of carnitine palmitoyltransferase 1 (P < 0.05), which was increased in high-energy groups (P < 0.05). In conclusion, BAs supplementation could increase growth performance, elevate carcass quality, and improve lipid metabolism in broilers.

Trichogramma, a genus of egg parasitoid wasps, are widely used as biological control agents and serve as model organisms in parasitoid research. Despite their significance, the understanding of RNA interference (RNAi) in Trichogramma remains very limited. In this study, we investigated RNAi-associated genes by bioinformatic approaches and experimentally assessed the feasibility of RNAi and the susceptibility of environmental RNAi in Trichogramma. We found that Trichogramma genomes contain a complete set of genes in the RNAi pathway and exhibit extensive gene expansion of dsRNase, which may influence RNAi efficiency by degrading dsRNA. We demonstrated successful RNAi through pupal microinjection in T. dendrolimi Matsumura, providing a technical approach for future gene functional studies. In addition, we observed no evidence of susceptibility to environmental RNAi in either T. dendrolimi adults or larvae, which might be attributed to the extensive expansion of dsRNase. This low environmental RNAi sensitivity in Trichogramma could suggest a reduced risk of RNAi-based pest management strategies affecting nontarget Trichogramma populations. Overall, this study presents a technical approach for conducting gene functional studies in Trichogramma and provides a foundation for evaluating the nontarget effects of RNAi-based pest control strategies on Trichogramma.