Effects and interaction of dietary calcium and non-phytate phosphorus for slow-growing yellow-feathered broilers during the starter phase

Low protein diet influences mineral absorption and utilization in medium-growing yellow-feathered broilers from 1 to 30 days of age

Reduced-protein diet can save protein ingredients and reduce nitrogen (N) losses. However, the effect of low protein diet on the mineral uptake and utilization in broilers needs to be explored. The aim of this study was to investigate the effect of low-protein diet on the growth performance, N deposition, mineral contents in serum, tissues and excreta, and the activities and gene expression of related enzymes in tissues of medium-growing yellow-feathered broilers, so as to elucidate the relationship between dietary protein level and the absorption and utilization of minerals in broilers. A total of 72 1-d-old Spotted-Brown male broilers were randomly allotted to 1 of 2 treatments with 6 replicate cages of 6 birds per cage for each treatment. The dietary crude protein (CP) levels for the two treatments were 21 % (the control treatment) and 19 % (low protein treatment), respectively. The experimental period was 30 d. The results showed that no differences (P > 0.05) were detected in average daily gain, average daily feed intake and feed: gain ratio of broilers during 1 to 30 d between the two treatments. However, low protein intake increased (P < 0.05) N retention rate, serum P, Cu and Mn, and excreta Cu, Mn and Zn, and decreased (P < 0.05) liver P and excreta P. In addition, birds fed low protein diet had higher (P < 0.05) manganese superoxide dismutase, and total superoxide dismutase activities in liver, and total antioxidant capacity and malondialdehyde content in heart, and lower (P < 0.05) copper-zinc superoxide dismutase (CuZnSOD) and succinate dehydrogenase activities in liver and CuZnSOD mRNA level in heart. In conclusion, the reduction of dietary CP content from 21 % to 19 % improved N retention, the absorption of P, Cu and Mn, as well as the antioxidant ability of liver and heart, and influenced metabolic utilization of P, Cu, Zn, Fe and Mn in medium-growing yellow-feathered broilers from 1 to 30 d of age.

Effects and interactions of dietary lysine and apparent nitrogen corrected metabolizable energy on yellow-feathered broiler breeder hens

BACKGROUND

Dietary lysine and apparent nitrogen-corrected metabolizable energy (AMEn) are two key variables affecting the production of breeder hens. In this study, the effects and interactions of lysine and AMEn on yellow-feathered broiler breeder hens were investigated. A total of 720 30-week-old breeder hens were fed in a 5 (lysine: 0.56%, 0.68%, 0.80%, 0.92%, and 1.04%) × 2 (AMEn: 11.50 and 11.10 MJ/kg) factorial arrangement for 12 weeks. The productive performance, reproductive traits, biochemical variables of breeder hens, the amino acid concentration and quality of eggs, and the growth performance of offspring broilers were determined.

RESULT

(1) Dietary lysine had quadratic effects (P < 0.05) on laying rate, average daily egg mass and feed intake/egg mass of breeder hens; birds with 11.50 MJ/kg AMEn (high AMEn) had higher (P < 0.05) BW than those with 11.10 MJ/kg AMEn (low AMEn); (2) dietary lysine significantly affected on the relative ovarian weight (quadratic and linear), and numbers of large yellow follicles (LYF, quadratic); birds with high AMEn had longer fallopian tube and more LYF than those with low AMEn (P < 0.05); (3) dietary lysine had significant effects (linear and quadratic) on eggshell thickness and shell strength of eggs from breeder hens; birds with high AMEn had thinner eggshells and deeper yolk color than those with low AMEn (P < 0.05); (4) there were higher (P < 0.05) contents of protein and concentrations of all measured animo acids (AAs) in eggs from birds fed low AMEn; (5) supplementation with high AMEn to breeder hens significantly increased the hatchability of fertilized eggs; (6) neither dietary lysine level or AMEn affected growth performance of offspring broilers; (7) both dietary lysine level and AMEn significantly affected gonadotropin concentrations and biochemical variables of breeder hens.

CONCLUSIONS

Dietary lysine had significant influences on productive performance, reproductive traits, and egg quality of yellow-feathered breeder hens. Based on productive performance, the optimal levels of dietary lysine were 0.81% to 0.83%, while 0.71% to 72% lysine was enough to obtain the best quality of breeding eggs. High AMEn was more beneficial to breeder hens for reproductive traits and hatchability of the fertilized eggs, while it showed detrimental effects on eggshell thickness and AA concentrations of breeding eggs.

Assessment of Non-Phytate Phosphorus Requirements of Chinese Jing Tint 6 Layer Chicks from Hatch to Day 42

We aimed to estimate the non-phytate phosphorus (NPP) requirements of Chinese Jing Tint 6 layer chicks. We randomly allocated 720 birds to five treatments with six cages of 24 birds each, feeding them a corn-soybean diet containing 0.36%, 0.41%, 0.46%, 0.51%, and 0.56% NNP. The results showed that the body weight gain (BWG), tibial length, and apparent total tract digestibility coefficients (ATTDC) of P were affected (p < 0.05) by dietary NPP level. A quadratic broken-line analysis (p < 0.05) of BWG indicated that the optimal NPP for birds aged 1-14 d was 0.411%. Similarly, 0.409% of NPP met tibial growth needs. However, 0.394% of NPP was optimal for P utilization according to the ATTDC criterion. For 15-42 d birds, 0.466% NPP, as estimated by the BWG criterion, was sufficient for optimal growth without decreasing P utilization. Using the factorial method, NPP requirements were calculated as 0.367% and 0.439%, based on the maintenance factors and BWG for 1-14 and 15-42 d birds, respectively, to maintain normal growth. Combining the non-linear model with the factorial method, this study recommends dietary NPP levels of 0.367% and 0.439% for 1-14 and 15-42 d birds, respectively, to optimize P utilization without affecting performance.

Dietary calcium and nonphosphate phosphorus interaction influences tibiotarsus development and related gene expression of broilers from 1 to 21 days of age

The dietary needs of calcium (Ca) and phosphorus (P) are interdependent, thus accurate evaluation of Ca and P requirements of broilers to support skeleton health and optimal growth is critical. The present study was carried out to investigate the effects of dietary Ca and nonphytate P (NPP) levels and their interactions on growth performance, tibiotarsus characteristics, tibiotarsus metabolism-related enzyme and proteins, and their gene expression of broilers, so as to provide a rational recommendation for Ca and NPP levels in diet. A total of 540 one-day-old Arbor Acres male broilers were randomly allotted to 1 of 15 treatments with 6 replicate cages of 6 birds per cage for each treatment in a completely randomized design involving a 5 × 3 factorial arrangement of treatments (5 levels of Ca × 3 levels of NPP). The birds were fed the corn-soybean meal diet containing 0.60%, 0.70%, 0.80%, 0.90%, or 1.00% Ca and 0.35%, 0.40%, or 0.45% NPP for 21 d. Dietary Ca level affected (P < 0.03) the bone mineral density, bone mineral content (BMC), breaking strength, ash percentage and ash Ca contents in tibia, which showed linear (P < 0.006) responses to dietary Ca levels. Dietary NPP level affected (P < 0.05) tibia BMC, ash percentage, and FGF23 mRNA level. Broilers that received 0.40% and 0.45% NPP had higher (P < 0.04) tibia BMC and ash percentage than those that received 0.35% NPP, but no differences (P > 0.05) were found between 0.40% and 0.45% NPP. Broilers that received 0.40% NPP had higher (P = 0.02) tibia FGF23 mRNA level than those that received 0.35% NPP, but no differences (P > 0.05) were detected between 0.40% and 0.45% NPP or 0.45% and 0.35% NPP. The interactions between dietary Ca and NPP affected (P < 0.05) ADG, ALP activity, bone gal protein, FGF23 contents, and the mRNA expression levels ALP and bone gal protein in tibia of broilers. Results from the present study indicate that dietary Ca and NPP interaction influences growth, tibiotarsus development, and related gene expression of broiler chickens. Considering all the criteria, the dietary levels of 0.90% Ca and 0.45% NPP would be optimal for both growth and tibiotarsus development of broilers fed a conventional corn-soybean meal diet from 1 to 21 d of age.

Integrated evaluation of the requirements and excretions of Cu, Fe, Zn, and Mn for broilers via a uniform design method

This study aimed to determine the ideal balance profile of Cu, Fe, Zn, and Mn for broilers of 1-21 days of age via a uniform experimental design. In Experiment 1, 900 1-day-old Arbor Acres male broilers were randomly allotted to 15 dietary treatments with six replicates of 10 birds. A total of 14 experimental diets were formulated with the supplementation of 8~16, 123~160, 40~80, and 60~120 mg/kg of Cu, Fe, Zn, and Mn, respectively, in the basal diet, according to the uniform design method. The excretion of Cu, Fe, Zn, and Mn in the manure and the broiler performance were determined to build the ideal balance profile of these elements. Experiment 2 was conducted based on the ideal balance profile built in Experiment 1, to test its practicability using 720 broilers with two treatments. The dietary concentrations of Cu, Fe, Zn, and Mn in the control group were 15.19, 203.08, 76.78, and 86.13 mg/kg, respectively. In Experiment 1, the concentrations of Cu, Fe, Zn, and Mn in the diets were 16.96, 166.66, 46.01, and 60.26 mg/kg, respectively, when the average daily gain reached the optimum value. When the dietary concentrations of Cu, Fe, Zn, and Mn were 8.54, 130.66, 38.19, and 64.07 mg/kg, respectively, the total excretion of Cu, Fe, Zn, and Mn got the minimum value. There are corresponding ideal balance profiles for minimum excretion of a certain element. In Experiment 2, the dietary levels of Fe, Zn, and Mn were decreased by 17.93%, 40.08%, and 30.04%, respectively, which had no significant effect on average daily gain, average daily feed intake, and feed gain for 1~21 day-old broilers but markedly decreased the excretion of Cu and Mn and total excretion. It was concluded that there is a dilemma between growth performance and mineral excretion. Although dietary levels of Cu, Fe, Zn, and Mn supporting optimal growth are higher than those for minimizing mineral excretion, supplementing too many trace elements in the diets of broilers is unnecessary.

The Use of Star Anise-Cinnamon Essential Oil as an Alternative Antibiotic in Prevention of Salmonella Infections in Yellow Chickens

Salmonella is capable of harming human and animal health, and its multidrug resistance (MDR) has always been a public health problem. In addition, antibiotic-free or antibiotic-reduced policies have been implemented in poultry production. Therefore, the search for antibiotic alternatives is more urgent than ever before. The aim of this study was to assess the antibacterial activity of star anise-cinnamon essential oil (SCEO) in vitro and its prophylactic effect against the infections of Salmonella pullorum, Salmonella give, and Salmonella kentucky in vivo. The results demonstrated that SCEO is effective against Salmonella pullorum, Salmonella give, and Salmonella kentucky in vitro. Supplementation with SCEO could significantly decrease the infections of Salmonella pullorum and Salmonella give, whereas it could slightly but not significantly decrease the infection of Salmonella kentucky, while also significantly alleviating the body weight (BW) loss caused by the infections of Salmonella pullorum, Salmonella give, and Salmonella kentucky in Yellow chickens. The SCEO had the best prophylactic effect against the infection of Salmonella give in Yellow chickens, followed by the infection of Salmonella pullorum and the infection of Salmonella kentucky. The SCEO, used as an antibiotic alternative, could be an effective prevention strategy against the infections of Salmonella pullorum, Salmonella give, and Salmonella kentucky in Yellow chickens.

Effects of dietary oligosaccharides on serum biochemical index, intestinal morphology, and antioxidant status in broilers

In order to determine the effect of different oligosaccharides on growth performance, intestinal health, and antioxidant status of broilers, 240 1-day-old XiangHuang broilers were randomly distributed to 4 treatments with 6 replicates each. Birds were fed corn-soybean-based diets (CON), and birds in xylo-oligosaccharides (XOS), fructo-oligosaccharides (FOS), and iso-maltooligosaccharide (IMO) groups were given the basal diet supplemented with 200 mg/kg XOS, FOS, and IMO, respectively. Result showed that average daily gain (ADG) during the whole 5 weeks in FOS group was greater than that in control group (p < 0.05). Both breast and thigh muscle percentages were higher for birds fed XOS versus CON (p < 0.05). Oligosaccharides supplementation increased jejunal villus height compared with control group (p < 0.05). Malondialdehyde (MDA) concentration in breast muscle was lower for birds fed diet containing FOS versus CON (p < 0.05). Activities of total superoxide dismutase (T-SOD) in serum and thigh muscle were higher in IMO than in control group (p < 0.05). Serum T-SOD and breast muscle's glutathione peroxidase (GSH-Px) activity was higher in XOS compared with control group (p < 0.05). Conclusion, dietary oligosaccharides such as XOS, FOS, and IMO could improve intestinal health and antioxidant ability of muscle without affect growth performance in broilers.