ABSTRACT
BACKGROUND: Xylanase and ß-glucanase combination (XG) hydrolyzes soluble non-starch polysaccharides that are anti-nutritional compounds. This study aimed to evaluate the effects of increasing levels of XG on intestinal health and growth performance of nursery pigs. METHODS: Forty pigs (6.5 ± 0.4 kg) were assigned to 5 dietary treatments and fed for 35 d in 3 phases (11, 9, and 15 d, respectively). Basal diets mainly included corn, soybean meal, and corn distiller's dried grains with solubles, contained phytase (750 FTU/kg), and were supplemented with 5 levels of XG at (1) 0, (2) 280 TXU/kg xylanase and 125 TGU/kg ß-glucanase, (3) 560 and 250, (4) 840 and 375, or (5) 1,120 and 500, respectively. Growth performance was measured. On d 35, all pigs were euthanized and jejunal mucosa, jejunal digesta, jejunal tissues, and ileal digesta were collected to determine the effects of increasing XG levels and XG intake on intestinal health. RESULTS: Increasing XG intake tended to quadratically decrease (P = 0.059) viscosity of jejunal digesta (min: 1.74 mPa·s at 751/335 (TXU/TGU)/kg). Increasing levels of XG quadratically decreased (P < 0.05) Prevotellaceae (min: 0.6% at 630/281 (TXU/TGU)/kg) in the jejunal mucosa. Increasing XG intake quadratically increased (P < 0.05) Lactobacillaceae (max: 40.3% at 608/271 (TXU/TGU)/kg) in the jejunal mucosa. Increasing XG intake quadratically decreased (P < 0.05) Helicobacteraceae (min: 1.6% at 560/250 (TXU/TGU)/kg) in the jejunal mucosa. Increasing levels of XG tended to linearly decrease (P = 0.073) jejunal IgG and tended to quadratically increase (P = 0.085) jejunal villus height to crypt depth ratio (max: 2.62 at 560/250 (TXU/TGU)/kg). Increasing XG intake tended to linearly increase the apparent ileal digestibility of dry matter (P = 0.087) and ether extract (P = 0.065). Increasing XG intake linearly increased (P < 0.05) average daily gain. CONCLUSIONS: A combinational use of xylanase and ß-glucanase would hydrolyze the non-starch polysaccharides fractions, positively modulating the jejunal mucosa-associated microbiota. Increased intake of these enzyme combination possibly reduced digesta viscosity and humoral immune response in the jejunum resulting in improved intestinal structure, and ileal digestibility of nutrients, and finally improving growth of nursery pigs. The beneficial effects were maximized at a combination of 550 to 800 TXU/kg xylanase and 250 to 360 TGU/kg ß-glucanase.
ABSTRACT
This study was carried out to evaluate the effects of supplementation with different levels of copper (Cu) and zinc (Zn), using two mineral sources (sulphate and hydroxy forms), on the bone characteristics, skin strength/elasticity, and haematological parameters of broilers. A total of 1792 1-day-old male Cobb-500 broiler chickens were randomly distributed among eight dietary treatments, using Cu sulphate (CSM) or hydroxychloride (CHC), and Zn sulphate (ZSM) or hydroxychloride (ZHC). The dietary treatments were as follows: (1) low-CSM/high-ZSM, (2) high-CSM/high-ZSM, (3) low-CHC/low-ZHC, (4) low-CHC/medium-ZHC, (5) low-CHC/high-ZHC, (6) high-CHC/low-ZHC, (7) high-CHC/medium-ZHC, and (8) high-CHC/high-ZHC. On Day 42, blood samples were collected from one bird/pen to analyze the haematological parameters. Finally, two birds/pen were slaughtered, and the tibia and femur were collected to analyze the quality of bone and skin. The means were subjected to ANOVA and, when significant, compared by Tukey's test (p < 0.05) or Dunnett's (p < 0.05) test. The haematological parameters were not influenced by mineral supplementation. However, the inclusion of low ZHC enhanced the skin strength compared to high ZHC (p = 0.046). Furthermore, the bone mineral density of the tibia proximal epiphysis, tibia ash and tibia mineral content were positively improved with supplementation of low-CHC/medium-ZHC compared to high-CHC/medium-ZHC. This study demonstrated that hydroxy compounds are potential alternatives for replacing sulphate supplements in broiler diets. Moreover, among the Cu and Zn levels, the low CHC (15 mg/kg) and medium ZHC (100 mg/kg) improved bone development and skin integrity, suggesting that the combination of Cu and Zn can be a nutritional strategy to prevent the incidence of leg disorders in broilers.