This study examined the prebiotic effects of xylooligosaccharides (XOS) on intestinal characteristics, gut microbiota, cecal short-chain fatty acids, plasma calcium metabolism, and immune parameters of laying hens. A total of 1,080 White Lohmann laying hens (28 wk of age) was assigned to 6 dietary treatments that included XOS at concentrations of 0, 0.01, 0.02, 0.03, 0.04, or 0.05% for 8 weeks. Each treatment had 6 replicates with 10 cages (3 birds/cage). Blood, intestinal tissues, and cecal digesta samples were collected from chickens at the end of the experiment. Villus height, crypt depth, the villus to crypt (VH: CD) ratio, and the relative length of different intestinal sections were evaluated. Additionally, the number of microorganisms and the content of short-chain fatty acids in cecal digesta samples were determined. Plasma concentrations of immunoglobulin A (IgA), immunoglobulin G, immunoglobulin M (IgM), interleukin 2 (IL-2), tumor necrosis factor-α(TNF-α), 1, 25-dihydroxyvitamin D3 (1,25(OH)2D3), calcitonin (CT), and parathyroid hormone (PTH) were also determined. The results showed that villus height and the VH: CD ratio of the jejunum were increased (linear, P < 0.01) with the increase in dietary XOS concentration, and the relative length of the jejunum (P = 0.03) was increased significantly in XOS diets. Dietary supplementation of XOS significantly increased (linear, P < 0.01) the number of Bifidobacteria in the cecum; however, total bacteria count, Lactobacillus, and Escherichia coli in the cecum were not affected by XOS supplementation. In addition, inclusion of XOS increased (linear, P < 0.01) the content of butyrate in the cecum; and the content of acetic acid showed a linear increasing trend (P = 0.053) with increasing concentration of XOS in the diets. Supplementation with XOS increased (quadratic, P < 0.05) the content of 1,25(OH)2D3 in plasma. There were no significant differences (P > 0.05) in the content of CT and PTH among dietary treatments. Furthermore, dietary XOS increased contents of IgA (linear, P < 0.05), TNF-α (linear, P < 0.05), IgM (linear, P < 0.05; quadratic, P < 0.05), and IL-2 (quadratic, P < 0.05). Taken together, it was suggested that supplemental XOS can enhance the intestinal health and immune function of laying hens by positively influencing the intestinal characteristics, gut microbiota, cecal short-chain fatty acids, and immune parameters.

The objective of this experiment was to determine the effects of dietary fiber levels on growth performance, gizzard development, intestinal morphology, and nutrient utilization in Cherry Valley meat ducks. In total, 720 1-day-old ducklings were fed with starter diets (120 ducklings, 8 pens of 15 ducklings, on each diet) containing 6 levels of crude fiber (CF, 1.46, 3.09, 4.15, 6.18, 7.52, and 9.03%, based on analysis) for 21 d. Then, on d 22, ducks fed all of the starter diets were transferred to a grower diet (containing 4% CF) to examine the residual effect of starter dietary fiber levels until 35 d. Body weight (BW), body weight gain (BWG), feed intake (FI), feed to gain ratio (F:G) were recorded/calculated weekly. Ducks were sampled for gizzard development and intestinal morphology determination on d 7, 14, and 21. Nutrient utilization was assessed using 25- to 27-day-old ducks. The results showed that BW (d 21), BWG (d 15 to 21, d 1 to 21), and F:G (d 15 to 21, d 1 to 21, and d 1 to 35) were increased quadratically (P < 0.01), and FI (all periods except for d 22 to 35) was increased linearly (P < 0.01), when starter dietary CF levels increased from 1.46 to 9.03%. Ducks under 3.09% and 4.15% CF starter diets had decreased 1 to 35 d FI and F:G when compared to ducks under other starter diets. When compared to ducks fed 1.46% and 3.09% CF starter diets, ducks fed starter diet containing 7.52% CF had increased gizzard development, jejunal morphology, energy retention, excreta nutrients availability, and standardized ileal digestibility (SID) of Arg, Ile, Leu, Thr, Val, Asp, Ala, Glu, Gly, Pro, Ser, and total amino acids. In conclusion, meat ducks from 1 to 21 d of age could adapt to a wide range (3.09% to 7.52%) of dietary fiber levels.

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The objective of the study was to investigate the effects of deficiency or high level addition of methionine (Met) in diet on homocysteine (Hcy) metabolism and hepatic lipid metabolism in broiler. A completely random design was used with 3 dietary treatments with the addition of Met from DL-methionine (DLM) at 0%, 0.22%, and 0.32% in a basal diet. The analyzed dietary Met was 0.271%, 0.485%, and 0.584% respectively for the Met-deficient, sufficient, and excessive diet. A total of 360 one-day-old male Ross 308 broiler chicks were randomly assigned to the treatments. The trial was last for 21 d. Compared to the Met-sufficient diet, the Met-deficient diet significantly resulted the decrease of 1 to 21 d growth performance and the increase of liver ether extract (EE). Compared to the Met-sufficient group, the expression of lipid transport gene apolipoprotein B (APOB) in both Met-deficient and Met-excessive group was decreased (P < 0.05). However, compared to the Met-sufficient group, a decreased of serum low-density lipoprotein cholesterol (LDLC) was only shown in birds fed a Met-deficient diet (P < 0.05). Although the plasma Hcy content was decreased, the expression of Cystathionine β-synthase (CβS) and hepatic inflammatory cytokines included interleukin-1 (IL-1) and interleukin-8 (IL-8) was significantly decreased in birds fed the Met-deficient diet when compared to those in Met-sufficient group (P < 0.05). When compared to the Met-sufficient group, the broilers in high dietary Met group had increased levels of catabolic enzyme genes expression especially acyl-coenzyme A oxidase 1 (ACOX1) and carbohydrate response element-binding protein (CHREBP) (P < 0.05), and a decreased content of liver EE. In conclusion, dietary Met deficiency decreased the hepatic lipid export and subsequently increased the hepatic lipid accumulation. High dietary Met addition increased the hepatic lipid catabolism and subsequently decreased the liver lipid accumulation.

1. The objective of this study was to evaluate the effects of total removal of dietary inorganic phosphorus and reduced energy and protein, without and with phytase supplementation, on the performance, egg quality and bone composition of laying hens. 2. Lohmann pink-shell hens were randomly assigned at 56 weeks of age to 5 treatments for 20 weeks as follows: (1) a positive control (PC) with 155 g CP/kg, 11·09 MJ ME/kg, calcium (Ca) 3·40% and non-phytic phosphorus (NPP) 0·26%, (2) a negative control (NC1) diet based on PC diet with Ca decreased to 3·30% and NPP to 0·14%, (3) NC2 diet was formulated on the basis of NC1 diet with 152·7 g CP/kg, 10·90 MJ/kg, (4) NC1 and (5) NC2 supplemented with phytase (300 FTU/kg) each. 3. Feed intake, hen-day or hen-housed egg production, egg number per hen-housed, and final body weight were depressed with NC1 and NC2 diets, but restored by phytase inclusion. There were no significant differences between the dietary treatments for feed conversion efficiency, rates of cracked and broken eggs, egg-shell thickness or egg-shell strength. Mortality was significantly increased by NC2 diet without phytase. Tibia ash was significantly decreased by both NC1 and NC2 diets. Bone strength, and Ca and P contents in tibia ash were significantly increased by phytase inclusion in the NC1 diet. 4. In conclusion, the NC1 and NC2 diets significantly depressed performance and tibia quality, but the addition of phytase (300 FTU/kg) significantly improved performance and tibia integrity.