The aim of the present study was to investigate the effects of dietary supplementation with different doses of rosmarinic acid (RA) on the growth performance, serum biochemical indices, liver antioxidant activity, and muscle nutritional component of broiler chickens during 1–20 days of age. A total of 1000 1-day-old Cobb 500 white-feathered broilers were divided into five groups. Each group included four replicates and 50 birds per replicate. The control group was the basic fodder group fed with a basal diet. The experimental groups included four levels of RA (100, 200, 300, and 400 mg/kg RA added to the basal diet, respectively). The results showed that a quadratic increase in final body weight (BW) and average daily gain (ADG) and a quadratic decrease in the feed/gain (F/G) ratio were observed with increasing dietary RA levels. At 200 mg/kg RA supplementation, growth performance was significantly improved. Moreover, under this RA treatment, the highest levels of total protein and globulin were detected in the serum, the activities of total superoxide dismutase and catalase in the liver of broilers were significantly increased, and the malondialdehyde content was significantly decreased, indicating a higher antioxidant capacity of the liver when 200 mg/kg RA was added to the basal diet. The flavor of the muscle meat was improved by dietary supplementation with 200 mg/kg RA. Therefore, adding 200 mg/kg of RA to the diet could significantly improve the growth performance of broilers, improve liver antioxidant capacity, and improve muscle quality, etc. The addition of RA to broiler feed as a natural antioxidant has great prospects.

This study aimed to investigate the effects of different defatting methods of black soldier fly (Hermetia illucens) larvae meal (BSFM) on the metabolic energy and nutrient digestibility in laying hens. Sixty young laying hens (Hy-Line W-36) aged 63 days were randomly divided into two groups (G1 and G2), each with five replicates of six hens housed in individual cages. Group G1 was fed 25% pressed black soldier fly meal (BSFMp) and 75% basal diet, and Group G2 was fed 25% extracted black soldier fly meal (BSFMe) and a 75% basal diet. Both diets included 5 g/kg chromium oxide as an external marker. A 7-day preliminary trial was followed by a 4-day experimental period. The results indicate that pressing and extracting significantly affected the digestibility of crude fat and total energy in BSFM, with BSFMp showing significantly higher crude fat digestibility than BSFMe. Similarly, total energy digestibility was also significantly higher in BSFMp. However, there were no significant differences in dry matter, organic matter, and crude protein digestibility between the two processing methods. The apparent metabolic energy values of BSFMp and BSFMe were 16.34 and 12.41 MJ/kg, respectively, showing a significant difference. The nitrogen-corrected metabolic energy values were 15.89 MJ/kg in BSFMp and 11.93 MJ/kg in BSFMe, indicating a highly significant difference. The digestibility of arginine and leucine in BSFMp was significantly higher than in BSFMe, while differences in lysine, cystine, threonine, tryptophan, and isoleucine were not significant. In conclusion, both defatting methods of BSFM had no adverse effects on the metabolic energy and nutrient digestibility in young laying hens, but BSFMp demonstrated better effects on the digestibility of metabolic energy and nutrients in the feed for young laying hens.

Black soldier fly larvae (BSFL) convert kitchen waste into high-quality insect feed. However, the optimal amount of auxiliary materials needed to improve the physical and chemical properties of kitchen waste and enhance BSFL bioconversion efficiency remains unresolved. In this study, maize stover and BSFL frass were added to kitchen waste (in groups G2 and G3, respectively) to explore their effects on the growth performance and bioconversion efficiency of BSFL. The group with only kitchen waste, without the addition of maize stover or BSF frass, was used as the control group and labeled as G1. On the 5th day, the body length of the BSFL in the G2 group was significantly greater than that in G1 and G3 (p < 0.05). The dry matter weight loss rate in the G3 group was significantly lower compared to that of G1 and G2 (p < 0.05), and the feed conversion rate (FCR) of G1 was significantly lower than that of G2 and G3 (p < 0.01). In summary, adding maize stover and BSFL frass increased BSFL feed intake and improved body weight gain. However, these additives did not significantly enhance BSFL bioconversion efficiency. The organic matter in maize stover and BSFL frass was utilized by the BSFL, and the heavy metal levels in each group of BSFL did not exceed standard limits.

In this study, a novel strain exhibiting heterotrophic nitrification was screened; subsequently, the strain was identified as Klebsiella pneumoniae LCU1 using 16S rRNA gene sequencing. The aim of the study was to investigate the effects of external factors on the NH₄⁺-N removal efficiency of strain LCU1 in order to elucidate the optimal conditions for NH₄⁺-N removal by the strain and improve the removal efficiency. The findings indicated that the NH₄⁺-N removal efficiency of the strain exceeded 80% under optimal conditions (sodium succinate carbon source, C/N ratio of 10, initial pH of 8.0, temperature of 30 °C, and speed of 180 rpm). The genome analysis of strain LCU1 showed that key genes involved in nitrogen metabolism, including narGHI, nirB, nxrAB, and nasAB, were successfully annotated; hao and amo were absent, but the nitrogen properties analysis determined that the strain had a heterotrophic nitrification ability. After 120 h, the NH₄⁺-N removal efficiency of strain LCU1 was 34.5% at a high NH₄⁺-N concentration of 2000 mg/L. More importantly, the NH₄⁺-N removal efficiency of this strain was above 34.13% at higher Cu²⁺, Mn²⁺, and Zn²⁺ ion concentrations. Furthermore, strain LCU1 had the highest NH₄⁺-N removal efficiency of 34.51% for unsterilised (LCU1-OC) aquaculture wastewater. This suggests that with intensive colonisation treatment, the strain has promising application potential in real wastewater treatment.

The aim of this study was to investigate the impact of incorporating black soldier fly meal (BSFM) into the diet of brooding laying hens, with a focus on growth performance, serum biochemical markers, nutrient digestibility, intestinal morphology, and immune responses. A total of 480 one-day-old chicks (Hy-Line Brown, commercial flock) were randomly divided into four dietary treatment groups, each consisting of six replicates with 20 birds per pen. One group was fed a basal control diet (control/G0 group), while the remaining three groups were fed 3% (G3 group), 6% (G6 group), and 9% (G9 group) BSFM, respectively. The study lasted for 42 days. At both 21 and 42 days of age, several parameters were measured, including average daily gain (ADG), average daily feed intake (ADFI), feed conversion ratio (FCR), and tibia length. Blood serum samples were also collected to assess biochemical and antioxidant indicators. Results showed that the ADG in the G3 group was significantly higher than the G0 group during the 1–21, 22–24, and 1–42 day periods (p < 0.05). The F/G ratio in the G3 group was significantly lower than that of the G0 group during the 1–21 day period (p < 0.05). However, there were no significant differences in ADFI or tibia length across the groups (p > 0.05). The total protein and globulin levels in the G3 and G6 groups were significantly higher than those in the G0 group (p < 0.05). Additionally, blood urea nitrogen levels in the G3 group were significantly higher than in the G0 group (p < 0.05). Conversely, triglyceride levels were significantly lower in the G3 and G6 groups compared to the G0 group (p < 0.05). Total antioxidant activity was significantly higher in the G6 and G9 groups than in the G0 group (p < 0.05). The treated groups also exhibited higher glutathione peroxidase (GSH-Px) activity and lower malondialdehyde (MDA) levels compared to the G0 group (p < 0.05). However, there were no significant differences in total superoxide dismutase activity across the groups (p > 0.05). In conclusion, this study indicates that BSFM can serve as a high-quality protein raw material in the process of laying hen breeding, highlighting its potential as a viable insect protein source in the poultry feed industry.

A microbial nest system (MNS) represents a novel and efficient approach to treating solid–liquid mixtures from pig farming instead of the conventional method, which separates the solid and liquid at first using centrifugation before treating the solid and liquid. However, the key environmental factors influencing the efficiency of this system and the microbial structure are still not clear. This study aimed to elucidate the changes in an MNS considering physicochemical properties, spectral analysis, and correlations between microbial community structures and environmental factors during the treatment. The results showed that the MNS underwent three temperature stages during the treatment process of piggery slurry: a warming period, a high-temperature period, and a cooling period. In the high-temperature period, the most abundant bacterium was Bacillus, with a relative abundance of 22.16%, and Chaetomium dominated the fungal community with a relative abundance of 11.40%. Moreover, the moisture content, pH value, and electrical conductivity (EC) exhibited an increasing trend, whereas the carbon-to-nitrogen (C/N) ratio and the ratio of ammonia nitrogen to nitrate nitrogen (NH₄⁺-N/NO₃⁻-N) showed a decreasing trend. The accumulation of humic acid and fulvic acid suggested that the humification process of organic matter was occurring. The moisture content and C/N ratio were identified as crucial factors influencing the bacterial and fungal community structures, respectively. This study provides a theoretical basis for enhancing the efficiency of piggery slurry treatment using an MNS and rational optimisation of the associated processes.