Recovery from adverse effects of heat stress on slow-growing chicks in the tropics 1: Effect of ascorbic acid and different levels of betaine

Three hundreds, 21 d-old slow-growing chicks were randomly divided among 5 treatments, of 5 replicates each. Each replicate contained 12 unsexed chicks housed in (1 × 1) a floor pen. A group was kept under thermoneutral condition at 28 ± 4°C and RH was 55 ± 3% during 21–84 d of age (positive control) and fed corn-soybean meal diet. The other four groups were kept for three successive days per week under heat stress (HS) at 38 ± 1.4°C and 49 ± 2% RH from 12.00 to 16.00 pm. Chicks in HS treatments were fed corn-soybean meal diet without (negative control) or with 250 mg AA/kg diet and Bet at 0.5 and 1 g/kg diet. HS decreased productive performance, increased (P < 0.05) meat dry matter, plasma triglyceride and serum calcium whereas decreased (P > 0.05) plasma glucose, serum total protein and water holding capacity (WHC) of meat. AA and 1 g of Bet/kg diet was equally potent for partial relief (P < 0.05) of the negative effect of HS on growth, increased (P < 0.05) feed intake, protein digestibility (P < 0.05), dressing out percentage, liver and giblets, whilst improved (P < 0.05) feed conversion ratio (FCR). Also, a complete recovery from the negative effect (P < 0.05) of HS shown on plasma glucose and partial recovery (P < 0.05) observed in total protein, triglyceride, blood pH, packed cell volume (PCV), hemoglobin (Hgb), rectal temperature (RT) and respiration rate (RR) and improved humoral immune competence to sheep red blood cell (SBRCs) test.     

水杨酸对黄花梨采后衰老和膜脂过氧化的影响

黄花梨果实采后用浓度为0.1 g/L,0.3 g/L的水杨酸(SA)溶液浸泡20 m in后,在(25±1)℃的贮藏条件下,研究了水杨酸处理对黄花梨果实采后衰老和膜脂过氧化的影响。结果表明,与以清水为对照相比,0.1 g/L SA处理能抑制SOD,CAT,POD活性的下降,降低果肉组织的相对电导率和MDA积累量,从而延缓了果实的成熟衰老;而0.3 g/L SA处理无明显影响。     

FSWM: A hybrid fuzzy-stochastic water-management model for agricultural sustainability under uncertainty

A hybrid fuzzy-stochastic water-management (FSWM) model is developed for agricultural sustainability under uncertainty, based on advancement of a multistage fuzzy-stochastic quadratic programming (MFSQP) approach. In MFSQP, uncertainties presented in terms of fuzziness and randomness can be incorporated within a multilayer scenario tree, such that revised decisions are permitted in each time period based on the realized values of the uncertain events. Moreover, fuzzy quadratic terms are used in the objective function to minimize the variation of satisfaction degrees among the constraints; it allows an increased flexibility in controlling the system risk in the optimization process. Results of the case study indicate that useful solutions for the planning of agricultural water management have been obtained. In the FSWM model, a number of policies for agricultural water supply are conducted. The results obtained can help decision makers to identify desired water-allocation schemes for agricultural sustainability under uncertainty, particularly when limited water resources are available for multiple competing users.     

Exogenous application of allelopathic water extracts helps improving tolerance against terminal heat and drought stresses in bread wheat (Triticum aestivum L. Em. Thell.)

The allelopathic water extracts (AWEs) may help improve the tolerance of crop plants against abiotic stresses owing to the presence of the secondary metabolites (i.e., allelochemicals). We conducted four independent experiments to evaluate the influence of exogenous application of AWEs (applied through seed priming or foliage spray) in improving the terminal heat and drought tolerance in bread wheat. In all the experiments, two wheat cultivars, viz. Mairaj‐2008 (drought and heat tolerant) and Faisalabad‐2008 (drought and heat sensitive), were raised in pots. Both wheat cultivars were raised under ambient conditions in the wire house till leaf boot stage (booting) by maintaining the pots at 75% water‐holding capacity (WHC). Then, managed drought and heat stresses were imposed by maintaining the pots at 35% WHC, or shifting the pots inside the glass canopies (at 75% WHC), at booting, anthesis and the grain filling stages. Drought stress reduced the grain yield of wheat by 39%–49%. Foliar application of AWEs improved the grain yield of wheat by 26%–31%, while seed priming with AWEs improved the grain yield by 18%–26%, respectively, than drought stress. Terminal heat stress reduced the grain yield of wheat by 38%. Seed priming with AWEs improved the grain yield by 21%–27%; while foliar application of AWEs improved the grain yield by 25%–29% than the heat stress treatment. In conclusion, the exogenous application of AWEs improved the stay green, accumulation of proline, soluble phenolics and glycine betaine, which helped to stabilize the biological membranes and improved the tolerance against terminal drought and heat stresses.     

Gustatory sensitivity of the external taste buds of Oreochromis niloticus L. to amino acids

The gustatory sensitivity of the Nile tilapia, Oreochromis niloticus L., to different amino acids was studied using an electrophysiological approach. The electrical responses were recorded from a branch of the facial nerve innervating the external taste buds of the upper lip. The relative stimulatory effectiveness (RSE) of nine amino acids and betaine were determined at a concentration of 1 mm and all of them elicited neural responses. This species responded well to the neutral, basic and acidic amino acids. The most stimulatory amino acids were L‐histidine, L‐arginine, L‐serine, L‐methionine and L‐glutamine; L‐proline and betaine were the least stimulatory. The results of this study suggest that the Nile tilapia has high external gustatory sensitivity to some amino acids as a physiological adaptation to search effectively for their sources. The effect of the pH, ranging from 4.0 to 9.0, on the RSE of three neutral amino acids and artificial pond water (APW) was also studied. The RSE increased below pH 6.0 and was relatively unaffected from 7.0 to 9.0, indicating that acidified stimulants are highly stimulatory in this species. Nile tilapia did not discriminate the pH of APW as effectively as some of the species studied earlier.     

五种微卫星DNA标记在肉牛群体中的研究

选择了分布在牛的4条染色体上的5个微卫星DNA标记IDVGA-2,IDVGA-27,IDVGA-46,IDVGA-55及TGLA-44,分析其在所供牛群体中的多态分布情况。结果表明,每个位点的等位基因个数及多态信息含量值分别为12/0.82,5/0.58,8/0.70,6/0.57和11/0.86。全部标记经半同胞家系检验,均符合孟德尔遗传规律。