The effects of ambient temperature and feeding regimens on cecum bacteria composition and circadian rhythm in growing rabbits.

Seasonal environmental shifts and improper eating habits are the important causes of diarrhea in children and growing animals. Whether adjusting feeding time at varying temperatures can modify cecal bacterial structure and improve diarrhea remains unknown. Three batches growing rabbits with two groups per batch were raised under different feeding regimens (fed at daytime vs. nighttime) in spring, summer and winter separately, and contents were collected at six time points in 1 day and used 16S rRNA sequencing to investigate the effects of feeding regimens and season on the composition and circadian rhythms of cecum bacteria. Randomized forest regression screened 12 genera that were significantly associated with seasonal ambient temperature changes. Nighttime feeding reduced the abundance of the conditionally pathogenic bacteria Desulfovibrio and Alistipes in summer and Campylobacter in winter. And also increases the circadian rhythmic Amplicon Sequence Variants in the cecum, enhancing the rhythm of bacterial metabolic activity. This rhythmic metabolic profile of cecum bacteria may be conducive to the digestion and absorption of nutrients in the host cecum. In addition, this study has identified 9 genera that were affected by the combination of seasons and feeding time. In general, we found that seasons and feeding time and their combinations affect cecum composition and circadian rhythms, and that daytime feeding during summer and winter disrupts the balance of cecum bacteria of growing rabbits, which may adversely affect cecum health and induce diarrhea risk.

Effects of Dietary 1,8-Cineole Supplementation on Growth Performance, Antioxidant Capacity, Immunity, and Intestine Health of Broilers.

This study was conducted to investigate the effects of 1,8-cineole on antioxidant capacity, immunity, and intestinal health of broilers. A total of 540 1-day-old Arbor Acres (AA) male broilers were randomly divided into five treatments with six replicates per treatment, and 18 broilers per replicate for 42 days. Dietary treatments were a corn−soybean meal basal diet supplemented with 0, and 10, 20, 30, and 40 mg/kg 1,8-cineole, respectively. Dietary supplementation with 20~30 mg/kg of 1,8-cineole increased the ADG from d 22 to 42 and d 1 to 42 (p < 0.05), and decreased the FCR (p < 0.05). Dietary supplementation of 10~40 mg/kg of 1,8-cineole increased total antioxidant capacity (TAOC) in serum (p < 0.05), and decreased malondialdehyde (MDA) level in the liver on day 21 (p < 0.05). The supplementation of 20~30 mg/kg of 1,8-cineole increased the activity of total superoxide dismutase (T-SOD) in the serum and liver and TAOC in the serum and the liver (p < 0.05), and decreased the level of MDA in the serum and the liver (p < 0.05) on day 42. Dietary supplementation with 20~30 mg/kg of 1,8-cineole increased serum immunoglobulin A, immunoglobulin G, and immunoglobulin M contents on day 21 (p < 0.05). On day 21, dietary supplementation of 20~30 mg/kg of 1,8-cineole increased the VH and VH/CD (p < 0.05) in the jejunum and ileum. The supplementation of 20~30 mg/kg of 1,8-cineole increased the content of secretory immunoglobulin A in the duodenum and ileum mucosa on d 42 (p < 0.05). In conclusion, dietary supplementation of 1,8-cineole improves the growth performance of broilers by enhancing antioxidant capacity, immunity, and intestinal morphology.

10-Hydroxy-trans-2-decenoic Acid, a New Potential Feed Additive for Broiler Chickens to Improve Growth Performance.

The purposes of this study were to explore the potential possibility of 10-hydroxy-trans-2-decenoic acid (10-HDA) use in feeding broiler chickens. A total of 216 healthy 1-day-old chicks were divided into 2 treatments at random (diets supplemented with 0 or 40 mg/kg 10-HDA, respectively) with 6 replicates of 18 birds each, and were then reared for 42 days. The results found that a diet supplemented with 10-HDA significantly increased average daily gain of broiler chickens in d 22~42 and d 0~42. Compared with the control group, dietary inclusion of 10-HDA markedly increased the serum concentrations of immunoglobulin (Ig) G at d 21, as well as IgM and interleukin (IL)-10 at d 42, while decreasing the levels of tumor necrosis factor (TNF)-α at d 21, as well as IL-6, TNF-α, and IL-1ß at d 42. Furthermore, broiler chickens fed a diet with 10-HDA had a higher (p < 0.05) serum activity of superoxide dismutase at d 42. Additionally, serum malondialdehyde content also decreased notably at d 21 and d 42. These results made it clear that 10-HDA increased the growth performance of broiler chickens, possibly by enhancing immune function and antioxidant capacity.

Effects of Fat Type and Exogenous Bile Acids on Growth Performance, Nutrient Digestibility, Lipid Metabolism and Breast Muscle Fatty Acid Composition in Broiler Chickens.

The current study aimed to explore the effects of fat type and exogenous bile acids (BAs) on growth performance, nutrient digestibility, lipid metabolism, and breast muscle fatty acids composition in broiler chickens. A total of 432 one-day-old Arbor Acres male broilers were stochastically distributed to a 2 × 2 factorial design comprised of two fat types (soybean oil and lard) and two levels of BAs (0 and 80 mg/kg) included in diets, totaling 4 treatments of 6 replicate pens with 18 chicks per replicate pen. Compared with treatments with soybean oil, dietary inclusion of lard increased the digestibility of ether extract (EE) in diets and the percentage of breast muscle on d 42, and increased the level of serum triglycerides and decreased serum alanine aminotransferase (ALT) activity on d 21 (p < 0.05). The level of saturated fatty acids, monounsaturated fatty acids (MUFAs), and the n-6 to n-3 polyunsaturated fatty acids ratio in breast muscle were also increased (p < 0.05) when feeding lard versus soybean oil. Dietary supplementation with BAs elevated average daily gain and reduced the ratio of feed to gain at d 0−21 and 0−42, significantly (p < 0.05). The digestibility of EE in diets and the percentage of breast muscle on d 42 were also increased by BAs (p < 0.05). Serum total cholesterol content as well as the percentage of abdominal fat on d 42, and ALT activity on d 21 were decreased when BAs were fed (p < 0.05). The concentration of total fatty acids, saturated fatty acids, and MUFAs of breast muscle were decreased by BAs. These results indicate that BAs can increase growth performance and nutrient digestibility, elevate carcass characteristics, and improve lipid metabolism, and their effects on nutrient digestibility and carcass characteristics were more pronounced in broiler chickens fed diets with lard.

Effects of dietary Bacillus amyloliquefaciens CECT 5940 supplementation on growth performance, antioxidant status, immunity, and digestive enzyme activity of broilers fed corn-wheat-soybean meal diets.

This experiment was conducted to investigate the effects of dietary supplementation with Bacillus amyloliquefaciens CECT 5940 (BA-5940) on growth performance, antioxidant capacity, immunity, and digestive enzyme activity of broiler chickens. A total of 720 one-day-old Arbor Acres male broiler chicks (average body weight, 45.87 ± 0.86 g) were randomly allocated to 5 treatments of 8 replicates with 18 chicks in each replicate. Broilers in the control group were fed a corn-wheat-soybean basal diet, the other 4 groups were fed the same basal diet supplemented with 500, 1,000, 1,500, or 2,000 mg/kg Ecobiol (1.27 × 109 CFU/g BA-5940) for 42 d, respectively. Broilers fed diets supplemented with BA-5940 showed a quadratic response (P < 0.05) of average daily gain (ADG) and feed to gain ratio (F:G) during d 22 to 42 and d 0 to 42. The glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities in serum and liver, and total antioxidant capacity (T-AOC) in liver of broilers on d 42 increased linearly (P < 0.05) with increasing levels of BA-5940, while malondialdehyde (MDA) level in serum decreased linearly (P < 0.05). Concentrations of serum immunoglobulin (Ig) A and IgM on d 21, and IgM on d 42 increased linearly (P < 0.05) as BA-5940 levels increased. Supplementation with increasing levels of BA-5940 linearly decreased serum tumor necrosis factor-α (TNF-α) levels on d 21 and 42, while increased interleukin (IL)-10 concentration (linear, P < 0.05) on d 21. Meanwhile, the levels of IL-1ß, IL-6, and TNF-α in the mucosa of jejunum and ileum were decreased (linear, P < 0.05) on d 42 as dietary supplementation of BA-5940 increased. Additionally, supplementation with BA-5940 also increased the activities of amylase (linear, P < 0.01), lipase (linear, P < 0.05) and chymotrypsin (linear, P < 0.01) in jejunal digesta, and lipase (linear, P < 0.05) in ileal digesta of broilers on d 42. To summarize, inclusion of BA-5940 in corn-wheat-soybean meal-based diet improved growth performance of broilers through improving antioxidant capacity, immunity, and digestive enzyme activity. Based on the results of this study, 1.1-1.6 × 109 CFU/kg BA-5940 is recommended for supplementation in broiler diets.

Effects of Manganese Hydroxychloride on Growth Performance, Antioxidant Capacity, Tibia Parameters and Manganese Deposition of Broilers.

This study was conducted to investigate the effects of dietary supplementation with manganese hydroxychloride (MHC) on production performance, antioxidant capacity, tibial quality, and manganese (Mn) deposition of broilers. A total of 756 one-day-old male Arbor Acres broilers were randomly allotted to 7 treatments of 6 replicates with 18 broilers per replicate. Broilers were fed corn-soybean meal basal diets supplemented of 100 mg/kg Mn as Mn sulfate (MnSO4), or 0, 20, 40, 60, 80, 100 mg/kg Mn as MHC for 42 days. The growth performance of broilers was not affected by dietary MnSO4 or MHC (p > 0.05), whereas the dressing percentage increased linearly (p < 0.05) with increasing of dietary MHC addition level. The activities of catalase (CAT) and manganese superoxide dismutase (MnSOD), and total antioxidant capability (T-AOC) in serum and liver on day 42 increased linearly (p < 0.05) with increasing of dietary MHC level, while malondialdehyde (MDA) concentration reduced linearly (p < 0.05). The length, strength, and density index of tibia increased linearly (p < 0.05) on day 21 as MHC supplementation level increased; there were no differences between MnSO4 group and 40-100 mg/kg Mn as MHC groups in tibial parameters of broilers (p > 0.05). As supplemental MHC levels increased, the Mn contents in heart, liver, kidney, and tibia increased linearly on day 42 (p < 0.05). In summary, dietary supplementation with MHC improved antioxidant capacity, bone quality, and Mn contents in broilers, but no effects on growth performance were detected. Based on the results of this study, dietary inclusion of 50-90 mg/kg Mn in the form of MHC to broilers is recommended.

Night-Restricted Feeding Improves Gut Health by Synchronizing Microbe-Driven Serotonin Rhythm and Eating Activity-Driven Body Temperature Oscillations in Growing Rabbits.

The circadian misalignment of the gut microbiota caused by unusual eating times in adult animals is related to disease development. However, whether the composition and diurnal rhythm of gut microbiota can be optimized by synchronizing the window period of eating with natural eating habits to reduce the risk of diarrhea remains unclear, especially in growing animals. In this study, 108 5-week-old weaned rabbits (nocturnal animals) were randomly subjected to daytime feeding (DF) and night-restricted feeding (NRF). At age 12 weeks, six rabbits were selected from each group, and caecum and cecal contents, as well as serum samples were collected at 4-h intervals during 24 h. Overall, NRF was found to reduce the risk of diarrhea in growing rabbits, improved the diurnal rhythm and abundance of beneficial microorganisms, along with the production of beneficial metabolites, whereas reduced the abundance of potential pathogens (Synergistes, Desulfovibrio, and Alistipes). Moreover, NRF improved diurnal rhythm of tryptophan hydroxylase isoform 1 and serotonin. Furthermore, NRF strengthened the diurnal amplitude of body core temperature, and promoted the diurnal expression of intestinal clock genes (BMAL1, CLOCK, REV-ERBα, and PER1), and genes related to the regulation of the intestinal barrier (CLAUDIN-1), and intestinal epithelial cell self-proliferation and renewal (BMI1). In vitro simulation experiments further revealed that synchronization of microbial-driven serotonin rhythm and eating activity-driven body temperature oscillations, which are important zeitgebers, could promote the diurnal expression of clock genes and CLAUDIN-1 in rabbit intestinal epithelial cells (RIEC), and enhance RIEC proliferation. This is the first study to reveal that NRF reprograms the diurnal rhythm of the gut microbiome, promotes the diurnal expression of clock genes and tight junction genes via synchronization of microbial-driven serotonin rhythm and eating activity-driven body temperature oscillations, thereby improving intestinal health and reducing the risk of diarrhea in growing rabbits. Collectively, these results provide a new perspective for the healthy feeding and management of growing animals.