Effects of stocking density on oxidative stress status and mammary gland permeability in early lactating dairy cows.

The current study was conducted to investigate the effect of stocking density (SD) on oxidative stress status and mammary gland permeability in early lactating dairy cows. Thirty-two dairy cows were allocated into 16 blocks, basing on parity, previous milk yield, and body weight, and were then randomly assigned into one of the two treatments as follows: 75% (75SD) and 100% (100SD) SD. The cows were fed with same diet throughout the 8-week experimental period. The milk yield and milk sample were collected on two consecutive days during the 8-week experimental period weekly. Plasma samples were collected on fourth and eighth experimental weeks. Raw, energy-corrected, and 4% fat-corrected milk yield were significantly higher in 75SD-cows than that of 100SD-animals, respectively. The milk somatic cell count was lower in 75SD-cows than that of 100SD-animals. The levels of Na+ , Na+ /K+ , bovine serum albumin and plasmin were lower in 75SD-cows than those of 100SD-cattle, respectively. The 75SD-cows had reduced insulin and insulin/glucagon levels but higher prolactin and growth hormone concentrations, compared with those of 100SD-animals, respectively. In conclusion, compared with low SD-animals, early lactating cows with higher SD had higher oxidative stress status, which further led to a greater mammary gland permeability.

Effects of different stocking densities on growth performance, antioxidant ability, and immunity of finishing broilers.

The study was conducted to evaluate the effects of different stocking densities on growth performance, antioxidant capacity, and immunity of broilers. One thousand four hundred and forty 22-day-old Lingnan Yellow broilers were randomly allotted to five different stocking density groups (8, 10, 12, 14, and 16 birds per m2 ). Each group consisted of three replicates. The results showed that 8 and 10 birds/m2 groups had higher average daily feed intake (ADFI) than the others (p < 0.05). Heat shock protein 70 (HSP70 ) in the group of 16 birds/m2 had the highest levels (p < 0.05). The group of 16 birds/m2 had the lowest total antioxidant capability (T-AOC) and total superoxide dismutase (T-SOD) activities in blood serum (p < 0.05), and significantly increased interleukin-1ß (IL-1ß) and interleukin-4 (IL-4) concentration compared to the groups of 8 and 10 birds/m2 (p < 0.05). In liver, the group of eight birds/m2 had higher T-AOC levels than that of 12, 14, and 16 birds/m2 (p < 0.05) and also higher catalase (CAT) activities than that of 14 and 16 birds/m2 (p < 0.05); the group of 10 birds/m2 had the highest T-SOD activities among all groups (p < 0.05). In conclusion, the above results suggest that stocking density of broilers up to 8 or 10 birds/m2 can prevent the negative effects on growth performance and welfare parameters in broilers.

Molecular diversity of rumen bacterial communities from tannin-rich and fiber-rich forage fed domestic Sika deer (Cervus nippon) in China.

BACKGROUND: Sika deer (Cervus nippon) have different dietary preferences to other ruminants and are tolerant to tannin-rich plants. Because the rumen bacteria in domestic Sika deer have not been comprehensively studied, it is important to investigate its rumen bacterial population in order to understand its gut health and to improve the productivity of domestic Sika deer. RESULTS: The rumen bacterial diversity in domestic Sika deer (Cervus nippon) fed oak leaves- (OL group) and corn stalks-based diets (CS group) were elucidated using 16S rRNA gene libraries and denaturing gradient gel electrophoresis (DGGE). Overall, 239 sequences were examined from the two groups, 139 clones from the OL group were assigned to 57 operational taxonomic units (OTUs) and 100 sequences from the CS group were divided into 50 OTUs. Prevotella-like sequences belonging to the phylum Bacteroidetes were the dominant bacteria in both groups (97.2% OL and 77% CS), and sequences related to Prevotella brevis were present in both groups. However, Prevotella shahii-like, Prevotella veroralis-like, Prevotella albensis-like, and Prevotella salivae-like sequences were abundant in the OL group compared to those in the CS group, while Succinivibrio dextrinosolvens-like and Prevotella ruminicola-like sequences were prevalent in the CS group. PCR-DGGE showed that bacterial communities clustered with respect to diets and the genus Prevotella was the dominant bacteria in the rumen of domestic Sika deer. However, the distribution of genus Prevotella from two groups was apparent. In addition, other fibrolytic bacteria, such as Clostridium populeti and Eubacterium cellulosolvens were found in the rumen of domestic Sika deer. CONCLUSIONS: The rumen of domestic Sika deer harbored unique bacteria which may represent novel species. The bacterial composition appeared to be affected by diet, and sequences related to Prevotella spp. may represent new species that may be related to the degradation of fiber biomass or tannins. Moreover, the mechanism and biological functions of Prevotella spp. in the rumen ecosystem, and synergistic interactions with other microorganisms should be noticed.

[Pollutant production and discharge from livestock and poultry industries and land carrying capacity in Zhejiang Province].

Based on the investigation of pollutant production and discharge from a typical scale pig farm in Zhejiang Province at three pig growth stages (piglets, fattening pigs, and sows) in the autumn and winter 2007 and the spring and summer 2008, the coefficients of pollutant production and discharge from the pigs as well as the total annual pollutant production and discharge from the farm were estimated. In the meantime, the annual application amount of animal manure to the farmlands in Zhejiang Province was estimated by using these coefficients and the livestock and poultry inventories in Zhejiang Province in 2007. It was estimated that the total amount of applied animal manure in the Province in 2007 was 2106.8 x 10(4) t x a(-1), containing 13.57 x 10(4) t x a(-1) of N, 6.7 x 10(4) t x a(-1) of P, 0.11 x 10(4) t x a(-1) of Cu, and 0.20 x 10(4) t x a(-1) of Zn. The pig-manure-equivalent farmland carrying capacity in the Province was 16.66 t x hm(-2) a(-1), and the average alarm limit was 0. 37. The application of animal manure in some areas of Zhejiang Province had exceeded the alarm limit for the land carrying capacity, and made a potential environmental threat.