不同浓度NAA/6BA配比对不同品种甘薯茎尖培养特性的影响

为明确不同品种甘薯茎尖培养的最佳NAA/6BA配比,设置0.1 mg/L/2.5 mg/L、0.2 mg/L/2.5 mg/L、0.2 mg/L/1.0 mg/L 3组NAA/6BA浓度配比处理,观测不同浓度激素处理对‘北京553’、‘红香蕉’、‘苏薯8号’、‘烟薯25’、‘安吉芋’、‘济徐23’、‘渝紫7号’、‘商薯19’茎尖培养成苗率、愈伤组织直径、不定根数目、叶片数和植株高度的影响,同时调查不同品种试管苗的移栽成活率。结果表明,‘红香蕉’、‘济徐23’、‘渝紫7号’、‘商薯19’在0.1 mg/L/2.5 mg/L的处理下培养效率最高;‘安吉芋’在0.2 mg/L/2.5 mg/L的处理下培养效率最高;‘苏薯8号’、‘北京553’、‘烟薯25’在0.2 mg/L/1.0 mg/L的处理下培养效率最高。因此,在甘薯茎尖培养过程中,不同甘薯品种适宜的NAA/6BA配比存在显著差异,在实际生产中应根据品种特性来进行调整激素的用量和比例。     

浮性水产饲料膨化加工参数优化研究

为优化浮性水产饲料挤压膨化加工参数，以膨化度、容积密度、吸水性和溶失率作为饲料加工品质评价指标，采用响应面分析法研究了螺杆转速、出料段机筒温度和物料含水率对饲料加工品质的影响，并利用扫面电镜观测了饲料微观形貌。结果表明：适中的螺杆转速、出料段机筒温度以及低物料含水率，有利于形成较高的饲料膨化度；高螺杆转速与高出料段机筒温度有利于形成较低的饲料容积密度、吸水性以及溶失率；优化后的浮性水产饲料膨化加工参数为螺杆转速130 r·min^-1，出料段机筒温度150 ℃，物料含水率10%，其加工后的饲料膨化度、容积密度、吸水性和溶失率分别为1.223、0.398 g·mL^-1、214.803%、4.297%；优化后的浮性水产饲料微观表面相对光滑圆润，物料的熔融效果较好，结构质密，饲料膨化加工综合质量较好。     

Effects of Dietary Protein and Lipid Levels with Different Protein‐to‐Energy Ratios on Growth,Feed Utilization,and Plasma Biochemical Parameters of Dianchi Golden‐line Barbell,Sinocyclocheilus grahami

An 8‐wk feeding trial was conducted to evaluate the effects of varying dietary protein and lipid levels with different protein‐to‐energy (P/E) ratios on growth, feed utilization, and plasma biochemical parameters of Sinocyclocheilus graham. Nine experimental diets were formulated to contain three protein levels (35, 40, and 45%), and each with three lipid levels (4, 8, and 12%), to produce a range of P/E ratios from 71.31 to 98.64 mg protein/kcal. Each diet was randomly assigned to triplicate groups of 25 fish. Fish grew best when fed the diet containing 45% protein and 12% lipid. However, fish fed the diet with 40% protein and 8% lipid had similar weight gain and specific growth rate as those fed the above diet but showed relatively better feed conversion ratio, protein efficiency ratio, and protein and energy retentions. Additionally, plasma total amino acids and blood urea nitrogen contents and γ‐glutamyltransferase, aspartate aminotransferase, and alanine aminotransferase activities in fish fed the diet containing 40% protein and 8% lipid were relatively low among the dietary treatments. These results may indicate that a diet containing 40% protein and 8% lipid with P/E ratio of 84.05 mg protein/kcal would be suitable for the optimal growth, feed utilization, and health of S. graham.     

Effects of supplementary feeds with different protein levels on growth and economic performances of Nile tilapia (Oreochromis niloticus) cultured in a rain-fed rice–fish ecosystem

This study investigated the effects of supplementary feeds with different crude protein (CP) levels on the growth and economic performances of sex-reversed Nile tilapia (Oreochromis niloticus) reared in a rain-fed rice–fish ecosystem for a period of 120 days. There were four treatments—namely, traditional feed (21% CP), formulated feed (26% CP), commercial feed (30% CP), and control (no feed was used)—with three replicates per treatment. Fish (30.04 g) were stocked in ditches at a rate of 0.5 fish m^?2 considering the total area and fed one of the tested feeds twice daily at the rate of 2%–5% of body weight. Water-quality parameters of the ditches were monitored fortnightly, and these parameters were found suitable for fish farming. Organic matter, total nitrogen, and available phosphorous in soil were increased significantly (P < 0.05) in the feed treatments after fish cultivation. Highly significant weight gain and SGR were observed with fish fed the commercial feed as compared with other treatments. The highest benefit-cost ratio (2.15) was found in the control, followed by formulated feed (1.90), but in the case of numerical net return, it was the opposite. However, commercial feed showed the lowest benefit-cost ratio (1.67) due to higher feed cost than other supplementary feeds. Therefore, this study suggests that fish fed with a formulated feed (26% CP) produced significantly higher net economic return in the rice–fish farming system.     

Effects of dietary protein and lipid levels on growth performance,fatty acid composition and antioxidant‐related gene expressions in juvenile loach Misgurnus anguillicaudatus

Dojo loach (Misgurnus anguillicaudatus) is one of the most important cultured freshwater fish in several East Asian countries. However, a little information is available in its nutritional requirements. Thus, this study was conducted to evaluate the effects of feeding varying levels of dietary protein and lipid on growth, fatty acid composition and antioxidant‐related gene expressions in juvenile loach. Six practical diets at three levels of protein (30%, 40% and 50%) and two levels of lipid (6% and 12%) were fed to loach juveniles (initial weight 0.40 g) in triplicated groups (20 fish per replicated) for a period of 8 weeks. Results showed that regardless of lipid level, body weight gain of fish was significantly increased with incremental dietary protein level. Meanwhile, feed conversion ratio was significantly decreased by dietary protein levels, and the lowest value was observed in fish fed dietary protein levels of 50%, regardless of dietary lipid level. Moreover, the percentage of 22:6n‐3 in viscera was significantly increased by different protein levels. The expression level of catalase was significantly increased with incremental dietary protein level with both lipid levels. Meanwhile, the expression level of hepatic nuclear factor erythroid 2‐related factor 2 (Nrf2) was downregulated with incremental dietary protein level with 6% of lipid level, but the expression was upregulated with incremental dietary protein level with 12% of lipid level. In conclusion, these data suggested that 6% lipid and 50% protein in diet was optimal for loach during early development stage.     

Sorghum extrusion process combined with biofortified sweet potato contributed for high iron bioavailability in Wistar rats

This study aimed to evaluate the effect of sorghum and sweet potato on the bioavailability of iron, gene expression of proteins involved in iron metabolism and the plasma antioxidant capacity in animals fed with whole sorghum grains processed by dry heat or extrusion, combined or not with sweet potato flour with high content of carotenoids. Five experimental groups were tested (n = 7): dry heat sorghum flour (DS); extruded sorghum flour (ES); whole sorghum flour + sweet potato flour (DS + SP); extruded sorghum flour + sweet potato flour (ES + SP) and positive control (FS). The evaluations included: hemoglobin gain, hemoglobin regeneration efficiency, gene expression of divalente metal transporter 1 (DMT-1), duodenal citochroma B (DcytB), ferroportin, hephaestin, transferrin and ferritin and total plasma antioxidant capacity (TAC). The ES + SP group showed higher (p < 0.05) expression of DcytB, ferroportin and hephaestin when compared to the control group. The DS group showed high (p < 0.05) expression of DMT-1 and the ES showed high mRNA expression of transferrin and ferritin. The changes in the sorghum physicochemical properties from extrusion process reduced the iron and phytate content, and increased the gene expression of proteins involved in iron metabolism, improving iron bioavailability. The combination of sweet potato and sorghum flour (dry or extruded) improved the iron capture and total antioxidant capacity, probably due to the presence of β-carotene and antioxidant compounds.     

氮素穗肥运筹对两个杂交中籼稻叶片形态、光合生产及产量的影响

【目的】为探究氮素穗肥不同促花肥和保花肥比例对水稻光合生产和产量的影响,并为水稻氮素穗肥管理提供依据,【方法】以株型和产量均存在较大差异的2个杂交中稻品种(德香4103和宜香3724)为材料,在常规施氮量(180 kg/hm2)下,研究了占总氮40%的穗肥不同促花肥和保花肥运筹比例(1∶3,2∶2,3∶1,4∶0)对水稻叶片生长、形态、光合生产及产量的影响。【结果】2个水稻品种均在低促花肥、高保花肥时(1∶3)表现出叶片直立、受光形态好,净光合速率高和群体干物质积累量大的特点,并最终获得较高产量;而在高促花肥、低保花肥下,2个水稻品种的剑叶、倒2叶叶面积和叶角增大,披垂度增加,群体质量变差,结实率和粒重下降,产量降低。德香4103因其颖花量较大,上3叶叶面积和总叶面积相对适宜,粒叶比高,且在不同穗肥运筹下叶面积和叶角变幅较小,因而受光姿态和群体质量更优,干物质积累量更大,产量更高。【结论】水稻氮素穗肥运筹应塑造良好叶片形态和群体质量,并增加花后物质积累量才能有助于产量提高;并对水稻株叶型选育进行了探讨。     

Effects of the dietary protein to energy ratio on growth,feed utilization and body composition in Macrobrachium nipponense

Oriental river prawn (Macrobrachium nipponense) has been widely cultured in Asian countries. However, its nutritional studies are very limited. In the present 8‐week study, we investigated the effects of dietary protein to energy ratio (P/E ratio) on the growth, feed utilization and body composition in juvenile M. nipponense (initial weight 0.302 ±0.03 g). Two‐factor experiment was designed and nine semi‐purified diets were formulated to contain three lipid levels (20, 80 and 140 g kg^?1) and three protein levels (330, 380 and 430 g kg^?1), producing P/E ratios from 16.5 to 23.4 mg KJ^?1 protein. The results indicated that the growth, survival rate and protein efficiency were dose dependently improved by the increased dietary lipid, but not dietary protein content. Increased dietary lipid content and/or protein content increased lipid accumulation in whole body, hepatopancreas and muscle, but did not change the feed intake and hepatopancreas weight. In conclusion, our present study indicated that M. nipponense is a species with relatively high‐energy requirement. It could utilize dietary lipid content up to 140 g kg^?1, while the dietary protein with more than 330 g kg^?1 would not promote growth and protein efficiency. Taken together, 330 g kg^?1 dietary protein and 140 g kg^?1 dietary lipid level with P/E ratio 16.49 could be optimum for M. nipponense.     

连续翻耕秸秆粉碎还田土壤物理性状及水稻产量

通过连续5年田间定位试验,研究了翻耕秸秆粉碎还田对稻麦两熟农田土壤物理性状、水稻产量及其构成因素的影响。结果表明,水稻收获时,翻耕秸秆粉碎还田处理能够有效降低耕层土壤容重、紧实度和土壤中固相部分所占比例,增加耕层土壤毛管孔隙度和土壤中气相部分所占比例。就水稻产量而言,翻耕秸秆粉碎还田处理较秸秆不还田处理有不同程度的提高,5年平均增产428 kg/hm~2,增幅为4.50%,主要是通过增加有效穗数和穗粒数来提高水稻产量。总之,本试验条件下,翻耕秸秆粉碎还田措施有利于改善耕层土壤物理结构,提高水稻产量。     

A new lean no time test baking method with improved discriminating power

In response to customer concerns related to gluten strength in commercial baking, the Canadian Grain Commission assessed whether the Canadian Short Process (CSP) test bake method was generating useful data related to intrinsic strength of wheat varieties. Assessment of CSP loaf volume data for Canadian variety trials spanning 2003 to 2013 showed very little correlation with dough strength parameters as measured by farinograph and extensigraph. A lean no time (LNT) test baking method was developed that can better discriminate genotypes and provide objective indicators of the effect of intrinsic dough strength on baking quality. From early method development, through method validation and verification using diverse sets of samples targeting different Canadian wheat classes and grown in three different crop years, results showed the LNT method to be more discriminating and easily adopted by other laboratories. In 2015, the LNT method was adopted as the method of choice in future Canadian variety registration trials. The LNT method is fast, simple and well-suited to high throughput test baking conditions encountered in the evaluation of large numbers of breeder lines. A new objective parameter, loaf top ratio, was also introduced and found to correlate well with dough strength and dough handling properties.