Four experiments were conducted to evaluate the nutrient contributions and physiological health benefits of spray-dried egg (SDE) containing only unfertilized eggs as a protein source in nursery pig diets. In all experiments, all diets were formulated to the same ME and Lys content, and each pen within a block (by BW) housed the same number of barrows and gilts. In Exp. 1 and 2 (168 and 140 pigs, respectively; 5 kg BW; 16 d old; 14 replicates/experiment), conducted at a university farm, treatments were with or without 5% SDE in a nursery control diet, which included antibiotics and zinc oxide. Pigs were fed for 10 d after weaning to measure ADG, ADFI, and G:F. The SDE increased (P < 0.05) ADG (Exp. 1: 243 vs. 204 g/d; Exp. 2: 204 vs. 181 g/d) and ADFI (Exp. 1: 236 vs. 204 g/d; Exp. 2: 263 vs. 253 g/d) compared with the control diet but did not affect G:F. In Exp. 3 (1,008 pigs; 5.2 kg BW; 20 d old; 12 replicates/treatment), conducted at a commercial farm, treatments were in a factorial arrangement of with or without SDE and high or low spray-dried plasma (SDP) in nursery diets, which included antibiotics and zinc oxide. Pigs were fed for 6 wk using a 4-phase feeding program (phases of 1, 1, 2, and 2 wk, respectively) with declining diet complexity to measure ADG, ADFI, G:F, removal rate (mortality plus morbidity), and frequency of medical treatments per pen and day (MED). The diets with the SDE increased (P < 0.05) ADFI during phase 1 only (180 vs. 164 g/d) compared with the diets without the SDE but did not affect growth performance during any other phases. The diets with SDE reduced MED during phase 1 (0.75% vs. 1.35%; P < 0.05) and the overall period (0.84% vs. 1.01%; P = 0.062) compared with the diets without the SDE but did not affect removal rate. In Exp. 4 (160 pigs; 6.7 kg BW; 21 d old; 10 replicates/treatment), conducted at a university farm to determine whether SDE can replace SDP, treatments were in a factorial arrangement of with or without SDP or SDE in nursery diets, which excluded antibiotics and zinc oxide. Pigs were fed for 6 wk using the same schedule used in Exp. 3 to measure ADG, ADFI, and G:F. The diets with SDE increased (P < 0.05) ADFI during phase 1 only (195 vs. 161 g/d) compared with the diets without SDE but did not affect growth performance during any other periods. In conclusion, SDE can be an efficacious protein and energy source in nursery pig diets and improves health and, in some instances, increases growth rate. 相似文献
Journal of Soils and Sediments - Determining soil extracellular DNA decomposition dynamics is essential to assessing lateral gene transfer possibility, nutrient-cycling efficiency, and the... 相似文献
This study aimed to understand the mechanisms of the variations in carbon (C) and nitrogen (N) pools and examine the possibility of differentiating the burning effects from seasonal and pre-existed N limitations in a native suburban forest ecosystem influenced by prescribed burning in subtropical Australia.
Materials and methods
Soil and litterfall samples were collected from two study sites from 1 to 23 months since last burnt. Soil labile C and N pools, soil C and N isotopic compositions (δ13C and δ15N), litterfall mass production (LM), and litterfall total C, total N, δ13C and δ15N were analysed. In-situ gas exchange measurements were also conducted during dry and wet seasons for Eucalyptus baileyana and E. planchoniana.
Results and discussion
The results indicated that labile C and N pools increased within the first few months after burning, with no correlations with climatic factors. Therefore, it was possible that the increase was due to the burning-induced factors such as the incorporation of ashes into the soil. The highest values of soil and litterfall δ15N, observed when the study was commenced at the experimental sites, and their high correlations with climatic factors were indicative of long-term N and water limitation. The 13C signals showed that soil N concentrations and climatic factors were also two of the main factors controlling litterfall and foliage properties mainly through the changes in photosynthetic capacity and stomatal conductance.
Conclusions
Long-term soil N availabilities and climatic factors were the two of the main driving factors of C and N cycling in the studied forest sites. Further studies are needed to compare soil and litterfall properties before and after burning to profoundly understand the effects of prescribed burning on soil labile C and N variations.
This study was conducted to evaluate the effects of composite antimicrobial peptide (CAP) on growth performance and health status in weaned piglets. Over 28 days, 36 weaned piglets (body weight, 10.58 ± 0.99 kg) underwent three treatments: negative control (NC, basal diet), positive control (PC, basal diet + 20 mg/kg colistin sulphate + 50 mg/kg kitasamycin), and CAP treatment (CAP, basal diet with 400 mg/kg CAP). Average daily gain of piglets fed the CAP diet was greater (P <0.05) than that of piglets fed the PC or NC diet during days 1–7, 8–14 and 15–21. Diarrhea rates of piglets fed the CAP or PC diet were lower (P <0.05) than those of NC‐fed piglets during days 1–7. Apparent total tract digestibility for dry matter and crude ash in CAP‐fed piglets was greater (P <0.05) than that of NC‐fed piglets. In the CAP group, Lactobacillus and Bifidobacterium counts were greater (P <0.05) and Escherichia coli counts were lower (P <0.05) than numbers for the NC group. Our results indicate that dietary CAP had beneficial effects on growth performance and health status in weaned piglets. 相似文献