Comparison of an intermittent, short-dawn/dusk photoperiod with an increasing, long-dawn/dusk photoperiod on broiler growth, stress, and welfare

Research Note: The effect of photoperiod on the NLRP3 inflammasome and gut microbiota in broiler chickens

The present study aimed to investigate the effect of photoperiod on the intestinal inflammation and gut microbiota. A total of 96 broiler chickens were divided into 2 groups and fed separately under 2 different photoperiods (12L:12D group and 23L:1D group) for 21 d. The results showed that the photoperiod of 23L:1D damaged duodenal tissue structure (intestinal villus erosion, mucosal epithelial cell detachment, and inflammatory cell infiltration), significantly increased the concentration of inflammatory cytokines (IL-1β, IL-18, IL-6, and TNF-α) and significantly increased the mRNA expression levels and protein expression levels of NOD-, LRR-, pyrin domain-containing protein 3 (NLRP3) and caspase1 (P <0.05) compared with 12L:12D, which indicating that extended photoperiod induced intestinal injury and activated NLRP3 inflammasome. 16S rRNA sequencing analysis revealed that Bacteroides was significantly decreased, Ruminococcus_torques_group, norank_f_Desulfovibrionaceae, GCA-900066575, Defluviitaleaceae_UCG-011, Lachnospiraceae_FCS020_group, norank_f_UCG-010 and norank_f_norank_o_Clostridia_vadinBB60_group and were significantly increased in the 23L:1D group, compared with the 12L:12D group (P < 0.05). The correlation analysis between differential microbial communities and intestinal inflammation showed that the relative abundance of Bacteroides was negatively correlated with the mRNA expression level of NLRP3 (P < 0.05) and the relative abundance of Ruminococcus_torques_group was positively correlated with the mRNA expression level of NLRP3 (P < 0.05). linear discriminant analysis (LDA) effect size (LEfSe) results (LDA > 4) showed that the relative abundance of Bacteroides was dramatically higher (P < 0.05) in the 12L:12D group, whereas the relative abundance of Ruminococcus_torques_group was noticeably higher (P < 0.05) in the 23L:1D group. By the comprehensive analysis of the gut microbiota, the interaction of gut microbiota (Bacteroides and Ruminococcus_torques_group) and NLRP3 inflammasome may contribute to the intestinal injury under the condition of extended photoperiod.

Effects of abrupt and gradual light/dark switching on growth performance, behavior, villus development, meat characteristics, and immunity of broilers

The aim of this study is to determine the effect of abrupt and gradual light/dark switching on growth performance, behavior, villus development, meat characteristics, and immunity of broilers. A total of 270 daily male broiler chicks were used in the experiment. The study comprised three groups based on whether the transitions between light and dark periods were abrupt or gradual. No significant differences were observed among the examined groups in terms of body weight, weight gain, mortality rate, feeding, pecking, relaxing, and feather preening behaviors, carcass, and breast meat quality characteristics. Total body weight gain, total feed consumption, total feed utilization ratio, and mortality rates of broilers during the 6-week fattening period did not differ compared to the abrupt transition. Broilers in the group with gradual transition exhibited less movement, more sitting, and sleeping behaviors. It was determined that the IgG was higher in the gradual transition group. The transitions between light and dark periods influenced the characteristics of thigh meat. Villus height and crypt depth were higher in the group where a 1-h gradual transition was applied. As a conclusion, gradual transition is more appropriate in broiler rearing.

Daylight exposure and circadian clocks in broilers: part I-photoperiod effect on broiler behavior, skeletal health, and fear response

The aim of this study was to examine effects of various daylight exposure during the 24-h light-dark (L-D) cycle on growth performance, skeletal health, and welfare state in broilers. Environmental photoperiod and related circadian clock, the 24-h L-D cycle, are important factors in maintaining productive performance, pathophysiological homeostasis, and psychological reaction in humans and animals. Currently, various lighting programs as management tools for providing a satisfactory environmental condition have been used in commercial broiler production. Four hundred thirty-two 1-day-old Rose 308 broiler chicks were assigned to 24 pens (18 birds/pen). The pens were randomly assigned to 1 of 4 thermal and lighting control rooms, then the birds were exposed to (n = 6): 1) 12L, 2) 16L, 3) 18L, or 4) 20L at 15 d of age. Lighting program effects on bird body weight, behavioral patterns, bone health, and stress levels were evaluated from d 35 to d 45, respectively. The birds of 12L as well as 16L groups, reared under short photoperiods close to the natural 24-h L-D cycle, had improved production performance, leg bone health, and suppressed stress reaction compared to the birds of both 18L and 20L groups. Especially, 12L birds had heavier final body weight and averaged daily weight gain (P < 0.05), higher BMD and BMC with longer and wider femur (P < 0.05), lower H/L ratio (P < 0.05), and more birds reached the observer during the touch test (P < 0.05) but spent shorter latency during the tonic immobility test (P < 0.05). Taken together, the data suggest that supplying 12 h as well as 16L of daily light improves performance and health while decreasing stress levels in broilers, making it a potentially suitable approach for broiler production.

Bird Welfare in Zoos and Aquariums: General Insights across Industries

Animal welfare is a priority across accredited zoological institutions; however, historically, research has been prioritized for mammals. Bird-focused studies accounted for less than 10% of welfare research in zoos and aquariums over the last ten years. Due to the lack of scientific publications on bird welfare, zoo scientists and animal practitioners can look to other industries such as agriculture, laboratories, and companion animal research for insight. This qualitative review highlights findings across industries to inform animal care staff and scientists on the welfare needs of birds within zoos and aquariums. Specifically, the review includes an overview of research on different topics and a summary of key findings across nine resources that affect bird welfare. We also highlight areas where additional research is necessary. Future welfare research in zoos and aquariums should prioritize studies that consider a diversity of bird species across topics and work to identify animal-based measures with empirical evidence. Moving forward, research from other industries can help develop innovative research on bird welfare within zoos and aquariums.

Compound Probiotics Improve Body Growth Performance by Enhancing Intestinal Development of Broilers with Subclinical Necrotic Enteritis

The aim of this study is to explore whether or not the combined application of BS15 and H2 is capable to have a more effective control effect on SNE in broilers. A total of 240 1-day-old female chickens were randomly divided into 5 groups: (a) basal diet in negative control group (NC group); (b) basal diet + SNE infection (coccidiosis vaccine + CP) (PC group); (c) basal diet + SNE infection + H2 pre-treatment (BT group); (d) basal diet + SNE infection + BS15 pre-treatment (LT group); and (e) basal diet + SNE infection + H2 pre-treatment + BS15 pre-treatment (MT group). The results showed the MT group had the most positive effect on inhibiting the negative effect of growth performance at 42 days of age. In the detection of the NC, PC, and MT group indicators at 28 days of age, we found that MT group significantly promoted ileum tissue development of broilers, and the ileum of broilers in the MT group formed a flora structure different from NC and PC, although it was found that the MT group had no effect on the butyrate level in the cecum, but it could affect the serum immune level, such as significantly reducing the level of pro-inflammatory cytokine IL-8 and increasing the content of immunoglobulin IgM and IgG. In conclusion, the composite preparation of Lactobacillus johnsonii BS15 and Bacillus licheniformis H2 could effectively improve the growth performance against SNE broilers, which is possibly caused by the improvement of the immune levels, the reduction of inflammation levels, and the promotion of the intestinal development.