Feeding low dietary levels of organic trace minerals improves broiler performance and reduces excretion of minerals in litter.

1. This experiment was conducted to evaluate the effect of organic and inorganic trace minerals in diets fed to 1872, one-day-old male Ross 708 broiler chicks. Two sources of supplemental trace minerals (inorganic or organic) and four trace minerals levels (12.5%, 25.0%, 37.5% or 50.0%) plus a positive control containing inorganic minerals at 100% of recommended levels according to Brazilian industry standards, were used in the diets. 2. When analysed with mineral source as the main factor, broilers fed diets containing organic minerals had better feed conversion (FCR) throughout the trial, until 48 d of age (1.754 organic vs. 1.783 inorganic; P < 0.05), improved liveability at 48 d (95.8% organic vs. 93.6% inorganic; P < 0.05) and higher weight gain at 48 d (3.941 kg organic vs. 3.881 kg inorganic; P < 0.05) compared to the inorganic trace mineral diets. At lower dietary inclusion levels (12.5% and 25%) the organic mineral-fed birds had a four-point improvement in FCR (P < 0.05). 3. Feeding organic minerals improved tibial ash at 48 d from 49.5% to 51.25% (P < 0.05). The P and Ca in the tibia at 48 d were significantly (P < 0.05) higher for the birds fed organic minerals (Ca: 17.4% vs. 18.7%; P: 8.8% vs. 9.4%, respectively). The lower levels of trace minerals in feed reduced the mineral concentration of Zn, Cu and Mn in the faeces and, hence, in the litter (P < 0.05). 4. Feeding organic minerals promoted a small, but statistically significant, drop in pH of breast meat compared to inorganic minerals at 48 d (5.83 vs. 5.86, respectively; P < 0.05). The organic mineral diets reduced drip loss in breast meat compared to inorganic trace mineral supplementation at 32 d of age, but not in older birds (2.46% vs. 3.77%, respectively; P < 0.05). 5. Oxidation status, measured by superoxide dismutase activity in breast muscle at 48 d of age, significantly increased with mineral inclusion levels (P < 0.001), irrespective of source. 6. It was concluded that the use of organic minerals, even at low levels in the diet, is beneficial for broiler performance and reduces the excretion of minerals in litter.

Genetic analysis of leg problems and growth in a random mating broiler population.

Improvement in growth has been widely reported as the cause of increased incidence of leg problems in broiler chickens. We report herein the genetic relationship between growth and leg problems in a random mating broiler control population. The traits studied were valgus (VL), varus (VR), and tibial dyschondroplasia (TD), which were expressed on a binary scale of 0 (normal) and 1 (abnormal); growth rates from 0 to 4 wk (BWG 0-4) and from 0 to 6 wk of age (BWG 0-6); and residual feed intake from 5 to 6 wk of age (RFI 5-6). A threshold-linear mixed model was employed for the joint analysis of the categorical and linear traits. Incidences of VL, VR, and TD were 26, 4, and 2%, respectively. Heritability of leg problems ranged from 0.11 to 0.13. Phenotypic correlations alluded to an unfavorable relationship between growth and leg problems; however, the genetic relationship between growth and leg problems was extremely weak, ranging from 0.01 to 0.08. There is, therefore, a basis for genetic improvement in leg problems. However, improved management practices would also be important to reduce incidence of leg problems in broiler chickens.

Genetic relationship between leg problems and bone quality traits in a random mating broiler population.

We herein report the genetic association between leg problems and bone quality traits in a random mating broiler control population. The leg problem traits were valgus (VL), varus (VR), and tibial dyschondroplasia (TD), and that of bone quality were shank weight (SW), shank length (SL), shank diameter (SDIAM), tibia weight (TW), tibia length (TL), tibia diameter (TDIAM), tibia density (TDEN), tibia breaking strength (TBS), tibia mineral density (TMD), tibia mineral content (TMC), and tibia ash content (TAC). A threshold-linear mixed model, implemented via a Bayesian approach, was employed for the joint analysis of the traits. Genetic correlations of leg problems with bone quality traits ranged from -0.06 to 0.11 suggesting that genetic relationship between leg problems and quality is weak, and management strategies could better alleviate leg problems than genetic improvement.

Morinda officinalis polysaccharides improve meat quality by reducing oxidative damage in chickens suffering from tibial dyschondroplasia.

Tibial dyschondroplasia (TD) is the common leg disease in commercial broilers. However, the effects of TD on meat quality and the protective of Morinda officinalis polysaccharide (MOP) are largely unknown. Three hundred broiler chicks (one-day-old) were equally allocated into control (CON), TD and MOP-treated groups for 15 days. The results indicated that TD influenced morphology and meat quality-related parameters of the breast muscle, and changed the activity and mRNA expression of antioxidant enzymes in plasma and breast muscles. Moreover, metabolomics profiling of breast muscle revealed that the main altered metabolites 4-guanidinobutyric acid and chenodeoxycholic acid, which are related to meat quality and oxidative stress. Additionally, 500 mg/L MOP effectively restored the content of meat metabolites and oxidative damage. These findings suggest that oxidative damage caused by TD may affect meat quality in broilers by changing the content of breast muscle metabolites and that MOP supplementation has a restorative effect.

Effects of a high dose of microbial phytase and myo-inositol supplementation on growth performance, tibia mineralization, nutrient digestibility, litter moisture content, and foot problems in broiler chickens fed phosphorus-deficient diets.

A total of 660 one-day-old Ross 308 broiler chicks were randomly distributed into eleven dietary treatments. Treatments included a maize-soybean meal-based diet with recommended calcium (Ca) and non-phytate phosphorus (nPP) (positive control; PC), an nPP-deficient diet (negative control; NC), NC diets supplemented with different levels of phytase (0, 500, 1,000, 2,000, 3,000, 4,000, 5,000, and 6,000 FTU/kg), a NC diet plus 0.15% myo-inositol, and a NC diet with reduced Ca level (Ca to nPP ratio same as PC). Feeding the NC diet had no effects on birds' body weight (BW), weight gain (WG), feed intake (FI), and feed conversion ratio (FCR), but decreased (P < 0.05) tibia P contents, crude protein (CP) digestibility, and serum P, but increased (P < 0.05) serum alkaline phosphatase (ALP) activity at 21 d of age. Phytase supplementation at ≥4,000 FTU/kg improved (P < 0.05) BW, WG and digestibility of nutrients. Feeding the NC diet resulted in greater (P < 0.05) litter moisture content (42 d) and poorer gait score (21 d), but 4,000 and 6,000 FTU/kg phytase returned (P < 0.05) these parameters to that of the PC. Supplemental myo-inositol increased (P < 0.05) serum total protein, P retention, and decreased (P < 0.05) litter moisture at 42 d of age. Feeding the low Ca NC diet increased (P < 0.05) serum total protein, ileum Ca, P, and CP digestibility and decreased serum ALP activity, litter moisture and gait score compared to the NC group. In conclusion, phytase in a dose-dependent manner, especially at ≥4,000 FTU/kg levels, was effective in overcoming the negative consequences of NC diets, primarily due to the ability to improve nutrient utilization. In addition, reducing the Ca level or supplementation of inositol of NC diet can correct some the negative effects of feeding a NC diet confirming the negative effect of a wide Ca: P ratio in a P-deficient diet and suggesting that inositol may play a role in the response to phytase addition.