黄羽肉鸡胴体冷藏时间对蒙山炒鸡食用品质的影响

研究黄羽肉鸡胴体冷藏时间（0～4 ℃,0、24、48 h）对蒙山炒鸡食用品质的影响。取蒙山炒鸡的鸡腿肉和鸡胸肉,测定其肉色、质地、pH值、系水率和挥发性物质含量等指标,并进行感官评定。结果表明：0 h组（对照组）和24 h组炒鸡鸡胸肉亮度值（L*）均显著高于48 h组（P＜0.05）;24 h组炒鸡的鸡腿肉L*显著高于0 h组和48 h组（P＜0.05）;0 h组和24 h组炒鸡的鸡腿肉和鸡胸肉硬度显著高于48 h组（P＜0.05）;感官评定结果表明,除48 h组香气评分显著降低（P＜0.05）、24 h组色泽评分显著升高（P＜0.05）外,各组滋味、组织形态评分及总分差异较小。因此,屠宰黄羽肉鸡后,宜冷藏24 h内炒制,以达到更好的食用品质。     

小麦基础日粮添加木聚糖酶对肉仔鸡消化道不同部位非淀粉多糖消化率的影响

通过在小麦基础日粮中添加国产酶（EⅠ）和进口酶（EⅡ）两种木聚糖酶制剂,研究了木聚糖酶对肉仔鸡各消化道食糜及粪中非淀粉多糖（NSP）消化率的影响。试验将7日龄肉仔鸡分成5组,分别为小麦对照组、小麦基础日粮中分别添加0．02％EⅠ、0．05％EⅠ、0．02％EⅡ和0．05％EⅡ的4个加酶组,饲喂至21日龄。结果表明：与对照组相比,4个加酶组均极显著提高了可溶性非淀粉多糖（SNSP）在嗉囊、空肠和粪中的消化率（P〈0．01）,显著提高了SNSP在回肠的消化率（P〈0．05）,且有提高其在肌胃中消化率的趋势（P〉0．05）。此外,加酶还极显著提高（P〈0．01）了不溶性非淀粉多糖（INSP）在粪中的消化率,显著提高（P〈0．05）了INSP在嗉囊和肌胃的消化率,EⅡ组回肠INsP消化率也显著高于（P〈0．05）对照组。     

Effect of diatomaceous earth on the performance and blood variables of broiler chicks during experimental aflatoxicosis

BACKGROUND: Diatomaceous earth (DE) is a type of tectosilicate found in large quantities in Iran. It is possible that this compound can absorb mycotoxins. An experiment was conducted to evaluate the protective effects of DE on experimental aflatoxicosis in broilers from 1 to 42 days of age. In four treatments of four replicates, 160 one‐day‐old Hubbard male chicks were subjected to two levels of aflatoxin B₁ (AFB₁) (0 and 1.0 mg kg^?1) and DE (0 and 30 mg kg^?1) RESULTS: Body weight gain, feed intake, feed conversion ratio, and productive efficiency index were adversely affected in the chicks treated with AFB₁. Weight of heart was significantly decreased (20.3%) by AFB₁ (P < 0.05). Serum total protein, albumin, and the activity of serum lactate dehydrogenase (LDH) were decreased by AFB₁. DE significantly (P < 0.05) increased body weight gain (9.51%), feed intake (7.44%), and improved feed conversion ratio (2.08%) as well as productive efficiency index (5.48%) in the birds that subjected to AFB₁ DE also increased serum albumin (22.6%), and the activity of serum LDH (44.4%). CONCLUSION: DE might be beneficial in reducing toxic effects of AFB₁ in broilers. It is possible to include DE as an alternative to other mycotoxin binders at levels of 30 mg kg^?1 in the diets on offer to broilers between the ages of 1 and 42 days. Copyright © 2007 Society of Chemical Industry     

Nutritional properties of fibre-rich barley products fed to broiler chickens

The chemical composition of roller-milled fractions of barley from a commercial plant was studied and a fraction rich in mixed-linked β-glucans selected. This fraction contained 560 g kg^?1 starch, 120 g kg^?1 crude protein, 170 g kg^?1 dietary fibre and 70 g kg^?1 mixed-linked β-glucans. An unprocessed, drum-dried or extrusion-cooked fraction was used as the major ingredient in diets for broiler chickens. The diets were fed with or without a supplementary fibre-degrading enzyme preparation in order to evaluate specifically the nutritional effects of the soluble dietary fibres. Processing significantly retarded growth, cumulative feed intake and feed conversion efficiency of the diets fed without enzyme supplementation, while the supplementation significantly improved all three parameters for each diet. Generally, processing decreased plasma triglycerides and total cholesterol and increased the ratio between high-density lipoproteins (HDL) and total cholesterol of chickens fed diets without enzyme supplementation. The enzyme supplementation increased the triglyceride and total cholesterol values and decreased the HDL/total cholesterol ratio, with more pronounced effects for chickens fed the processed diets.     

Hot extraction and characterization of a ligninlike fraction involved in larvicidal effects of decomposed leaf litter against mosquito

Hot water-extraction was performed on decomposed leaf litter in order to solubilize the toxic fraction involved in the dietary interaction against mosquito larvae in subalpine breeding sites. The toxic fraction was partially extracted by water with an optimum temperature of 60°C and recovered in an insoluble form. Phytochemical characterization was achieved through differential enzymatic hydrolyses, using the laccase mediator delignifying system, and aluminum chloride chelation monitored by standard bioassays; comparative spectrophotometric analyses in ultraviolet light after solubilization in acetyl bromide; and comparative reversed-phase high-performance liquid chromatography of the phenolic aldehydes after alkaline nitrobenzene oxidation. The results suggested the involvement of ligninlike compounds in the toxicity of the isolated fraction. Toxicity of this fraction appeared far stronger than that of the crude leaf litter. The involvement of this ligninlike fraction in the dietary toxicity of leaf litter against larval mosquito was then investigated.     

用择优腐蚀技术制作MMI型GaAs光功率分配器

通过对器件结构进行优化设计和择优腐蚀技术 ,用 H3 PO4 - H2 O2 - H2 O系腐蚀液制作了能直接与单模光纤阵列相耦合的 MMI型 Ga As1× 4光功率分配器 .最后用 1 .3 μm波长的He- Ne激光进行了测试 ,发现该器件基本实现了功率均分要求 ,功率离散度为 0 .1 55d B.     

长白山6 种主要森林类型地表凋落物燃烧性实验研究

以长白山黄松蒲林场6 种主要森林类型林地内凋落物为对象,研究长白山林区地表凋落物的燃烧性。在长白山黄松蒲林场的白桦林、针叶混交林、针阔混交林、落叶松林、阔叶混交林和杨树林6 种主要森林类型林地内设置样地,通过外业调查、混合采样的方式收集地表凋落物并进行燃烧实验,测定火蔓延传播的速度、燃烧温度和质量变化。通过改变实验风速、坡度和坡向,研究不同条件对火行为、火蔓延速度和烧损率的影响。实验结果表明：长白山地区地表凋落物的火强度从大到小排序为白桦林、针叶混交林、针阔混交林、落叶松林、阔叶混交林、杨树林,白桦林的火强度最大,为460.23 kW/m,杨树林的火强度最小,为367.09kW/m;风速越大,地表凋落物火蔓延速度越大;风速为6 m/s 时,燃烧过程平均温度最大,烧损率最高,当风速小于2 m/s 或大于8 m/s 时,可燃物无法完全燃尽;上坡火坡度增加时,地表凋落物的火蔓延速度增加,烧损率减小;下坡火坡度增加时,地表凋落物的火蔓延速度减小,烧损率增加。     

The effects of sorghum proanthocyanidins on digestive enzyme activity in vitro and in the digestive tract of chicken

The effects of sorghum grain proanthocyanidins (PAs) on the digestive enzyme activity of broiler chickens were investigated in vitro and in vivo using seven sorghum varieties grown in Zimbabwe. All seven sorghum varieties, classified as either high‐PA (DC‐75, Mutode, Red Swazi and Chirimaugute) or low‐PA (SV2, Brown Tsweta and Chibonda), were used to assess the PA–protein binding capacity and inhibition of trypsin and amylase in vitro. Three of the varieties (Chirimaugute, Chibonda and Brown Tsweta) were subsequently used in broiler diets to test the effects of PAs on the growth performance and digestive enzyme activity of 48 broiler chicks at 42 days of age. Protein precipitation and trypsin and amylase inhibition increased (P < 0.05) with an increase in level of PAs from the low‐PA varieties (by 1–10%) to the high‐PA varieties (by 40–70%). The activity of trypsin in the duodenal lumen of chicks fed the control diet was almost double that of chicks fed Chirimaugute. Amylase activity in the high‐PA group was lowered significantly (P < 0.01) relative to the control and low‐PA groups. The difference between in vitro and in vivo residual enzyme activities was 10–20% for amylase and 5–10% for trypsin. Chicks fed the high‐PA diet showed lower performance than chicks fed the control and low‐PA diets. Mean body weight gains were 59.9, 34.4, 57.3 and 61.4 (SE 4.02) g day⁻¹, final weights were 1936.4, 1363.3, 1773.2 and 1857.0 (SE 78.5) g and feed efficiencies were 1.85, 2.26, 1.65 and 2.13 (SE 0.014) for the control, Chirimaugute, Brown Tsweta and Chibonda groups respectively. The results indicate that PA–enzyme interaction, in addition to dietary protein–PA binding, contributes to the poor performance of chickens fed high‐PA sorghum diets. © 2000 Society of Chemical Industry     

Full-fat sunflower seed as a protein source for broiler chicks

The protein quality of hulled full-fat sunflower seed (HFFSS) was evaluated and compared to that of soyabean meal in two experiments with broiler chicks. In the first experiment, PER and NPR indexes were determined. The results showed that, when fed as the sole source of dietary protein (90 g crude protein kg⁻¹ diet), the performance as well as PER and NPR values of chicks fed HFFSS were much poorer than those of chicks fed soyabean meal. The protein quality of HFFSS was improved greatly by lysine supplementation. The PER and NPR values for HFFSS supplemented with 0.2 and 0.4% of L -lysine equalled and even became superior to those estimated for soyabean. In the second experiment, apparent and true ileal digestibilities of nitrogen and amino acids were calculated. The apparent but not the true digestibility of the mean of amino acids was significantly lower (P < 0.01) in HFFSS than in soyabean meal (0.838 vs 0.902 and 0.932 vs 0.957, respectively). The results also showed that lysine from HFFSS was less digestible than that from soyabean meal, the apparent as well as the true digestibility values being lower in the former. © 1999 Society of Chemical Industry     

Effect of particle size of pea (Pisum sativumL) flours on the digestion of their proteins in the digestive tract of broilers

Pea (Pisum sativum L) protein digestion in relation to particle size was studied in broilers. Birds were fed coarse pea (CP) or fine pea (FP) or nitrogen-free (NF) diets. Protein digestion was studied in gastro-intestinal contents of chicks by gel filtration and electrophoresis. Apparent ileal protein digestibility was lower for CP (70·2%) than FP (89·5%) diets. A decrease of protein digestibility appeared between ileum and excreta for FP diets. Endogenous proteins in ileal digesta represented important amounts. Estimation of excreta composition was about 24% of microflora in FP and CP. The molecular weight (MW) dis-tribution of nitrogen compounds of diets were characterised by high proportions of components with MW>15000. The relative amounts of very low MW (<500) components were in all cases lower for CP than for FP digesta. In intestine, proportions of high MW (>15000) components were higher for CP than for FP fed birds. Intestinal digesta of NF diet were characterised by higher MW than FP digesta. Similar electrophoresis patterns appeared for CP digesta and pea diet, whereas fine particles of CP and FP showed disappearance of protein bands. It is concluded that the CP diet leads to lower digestion of proteins than FP, but FP diets can lead to low MW proportion in intestine, which could be a limiting factor in pea protein digestion. © 1997 SCI.