Bacteriological Analysis and Public Health Impact of Broiler Meat: A Study on Nalitabari Paurosova, Sherpur, Bangladesh

Broiler meat is one of the most important protein sources for Bangladeshi people. Food-borne diseases associated with the consumption of poultry meat and its processed products are of public health concern worldwide. An investigation was conducted to assess the bacteriological quality of poultry meat from some poultry farms and its health impact on consumer of Nalitabari paurosova, Sherpur district, Bangladesh. Total 15 samples were randomly selected and collected from different poultry farms on the basis of farms level and size. Bacteriological quality of the samples was assessed by following the standard microbiological methods. The health impact was evaluated with the help of semi-structured based questionnaire of 400 peoples. The average value of TVC and TCC were found as 4.3 × 106 CFU/g and 3.6 × 104 CFU/g respectively. In this study, the prevalence of fecal coliform was recorded as 33% and the presence of E. coli in 53% samples. The mean value of Salmonella spp. of meat samples was 4.6 × 103 CFU/g. No Shigella spp., Vibrio spp. and fungal species were detected in any sample. Some selected isolates were tested for their sensitivity against some commercially available common antibiotics used in Bangladesh. E. coli was 80% resistance to Ampicillin and 90% sensitive to Ciprofloxacin whereas Salmonella spp. showed 100% resistance to Ampicillin and 80% sensitivity to Ciprofloxacin. The antibacterial activity of renowned medicinal plant Azadirachta indica was also evaluated against some multidrug resistance bacteria. The inhibitory zone of both 30% methanolic and ethanolic extracts of Azadirachta indica was 12 mm and 12.3 mm, where 40% methanolic and ethanolic extracts were 14 mm and 16.3 mm against E. coli. The 40% ethanolic extract showed the better activity between them. The plant extract has no activity against Salmonella spp.. Awareness and health impact of broiler meat was determined among the people of different sectors on the basis of educational qualification, socio-economic condition, income source, broiler meat intake pattern, BMI range and food related diseases they have suffered. The peoples who eat broiler meat are much more prone to complicated diseases than the peoples who never eat it. So broiler meat intake pattern must be changed for better health. The widespread occurrence of Salmonella spp. and E. coli in poultry meat also reinforces the need for effective control measures.

Fatty Acid Deposition on Broiler Meat in Chickens Supplemented with Tuna Oil

The aim of the present study was to evaluate the effect of feeding four levels of tuna oil on performance and fatty acid (FA) profiles of broiler chicken meat. 240 Ross broiler chickens were randomly assigned to 20 pens and divided into four treatments: 0%, 0.75%, 1%, and 1.25% of tuna oil. At 49 days, breast and legs-thighs muscles were processed for FA analysis. Concentrations of FA in legs and thighs meat were significantly higher when compared with breast meat. In both types of meats (breast and legs-thighs), the inclusion of 1.0% or 1.25% of tuna oil in the diet significantly increased (P < 0.05) the concentration of n-3 FA (especially docosahexaenoic and eicosapentaenoic acids). Fat in broiler breast contained a proportion of 29% saturated FA (SFA): 36% monosaturated FA (MFA): 35% polyunsaturated FA (PUFA);while legs and thighs meat had a proportion of 28% SFA: 38% MFA: 33% PUFA. The addition of tuna oil in the broiler diet significantly reduced the deposition of SFA, MFA, and PUFA in breast meat, while in legs and thighs these reductions were less noticeable. The significant reduction in the concentration of n-6 PUFA and the increment of n-3 PUFA were more evident in breast than in legs and thighs, and with the addition of 1% and 1.25% of tuna oil. The results of the present study suggest a difference in FA deposition attributable to supplementation with tuna oil. The addition of tuna oil could be recommendable to increase n-3 PUFA in both broiler chicken breast and legs-thighs meats, providing a healthier and functional chicken meat to consumer.

Effects of dietary tryptophan and stocking density on the performance,meat quality,and metabolic status of broilers

Background： Highly automated cage-rearing systems are becoming increasingly popular in China. However, a high stocking density can cause oxidative stress and decrease broiler performance. The tryptophan （TRP） derivative 5-hydroxytryptophan （5-HT） has been shown to preserve membrane fluidity in birds suffering from oxidative stress Therefore, this experiment was conducted to determine the effects of dietan/TRP supplementation on performance, breast meat quality and oxidative stress in broilers reared in cages with a high or low stocking density. Methods： Female Arbor Acres broilers （25-d-old, n = 144） were randomly allocated to 1 of 4 treatments. The birds were fed a diet based on corn, soybean meal, cottonseed meal and corn gluten meal containing either 0.18 or 0.27% TRP and were housed with stocking densities of 11 or 15.4 birds/m2 in a 2 x 2 factorial experiment. Broiler performance was evaluated from d 25 to 42. Eight birds from each treatment were slaughtered on d 42 and plasma and breast muscle samples were collected to measure biochemical indices. Results： A higher stocking density tended to be associated with reduced weight gain （P 〈 0.10）, and significantly increased plasma glutamic-pyruvic transaminase （GPT） activity （P 〈 0.001）. Increased dietary TRP significantly reduced the activities of lactic dehydrogenase and GPT while increasing total cholesterol in the plasma （P 〈 0.01）, reducing drip loss of breast muscle （P 〈 0.10） and improving feed efficiency （P 〈 0.10）. Conclusions： An increase in dietary TRP, ].S-fold higher than the standard supplementation level, can alleviate oxidative stress as well as improve welfare and feed efficiency in broilers reared in cages with a high stocking density.

Effects of Dietary Isoflavone Supplementation on Meat Quality and Oxidative Stability During Storage in Lingnan Yellow Broilers

To investigate the effects of a synthetic isoflavone （SI） on meat quality and oxidative stability, 1 500 43-d-old Lingnan yellow male broilers were randomly assigned to five dietary treatments： diets supplemented with 0, 10, 20, 40, or 80 mg SI kg-1, fed ad libitum for a period of 3 wk. After refrigerated storage, a＊ value of the meat increased with dietary SI supplementation using 10 and 40 mg kg-1 level （P〈0.05）, L＊ value decreased （P〈0.05）, and 40 mg kg-j increased the pH （P〈0.05）. Supplementation with SI, at all levels, increased water holding capacity （P〈0.05） and decreased lactic acid content of meat （P〈0.05）. The concentration of malondialdehyde at 72 h decreased linearly （P=0.005） and quadratically （P=0.004） with increasing levels of SI. Dietary SI at 20 and 40 mg kg-1 levels enhanced total superoxide dismutase activity in meat （P〈0.05）. Meat pH quadratically decreased as the storage time increased （P〈0.05）, with the highest value at 24 h （P〈0.05）. Lactic acid and malondialdehyde concentrations of meat increased over time, with value at 96 h being far higher than at earlier times （P〈0.05）. Supplemental SI linearly and quadratically increased the mRNA abundance ofglutathione peroxidase （GPX） （P=0.001 and P=0.002） and catalase （CAT） （P=0.003 and P=0.006） in breast muscle. The results from this study indicate that dietary supplementation with SI can improve meat quality during refrigerated storage by decreasing lipid peroxidation and enhancing oxidative stability and, for male broilers from 43 to 63 d of age, the optimal level of SI was 40 mg kg-1.

Effects of Non-starch Polysaccharide Enzyme Products on Meat Performance in Broilers

[ Objective] To investigate the effects of non-starch polysaccharide （NSP） enzyme products on meat performance of broilers and thus to provide a scientific basis for their rational use. [Method] Two hundred 21-day-old Ross broilers were assigned to five groups. The broilers in group Ⅰ and group Ⅱ were fed positive control diet and negative control diet, respectively, which were slightly different. The broilers in group Ⅲ, Ⅳ and V were fed the negative control diet respectively supplemented with different commercial NSP enzyme products. The broilers were slaughtered at 56 days old, and their meat yield was determined. [ Result] The percentage of carcass yield and percentage of abdominal fat were significantly higher in the group Ⅲ than in the group Ⅱ （P 〈 0.05）. The percentage of small intestine weight in slaughter weight was lower in the group Ⅱ than in other groups. [ Conclusion] Diets supplemented broad-rang and highly active NSP enzyme products can promote absorption of routine feed ingredients, increase meat yield, and improve meat performance.

Effects of Non-starch Polysaccharide Complex Enzymes on Meat Quality in Broilers

[Objective] The study aimed to research the effect of several commercial NSP complex enzymes products on broiler meat quality, and provide scientific basis for feed enterprise and breeding farmers choosing NSP complex enzymes. [ Method] Two hundred ROSS broilers at age of 21 days were designed to five treatment groups, including the positive and negative control treatments, and Group 1 to 3 with feed additive of the commercial non-starch polysaccharide complex enzymes each on base of the negative group diet. At 56 days of age, broilers were killed and meat quality was analyzed. [ Result] The thigh meat color CIELAB a value for the negative control broilers was lower （ P 〈 0.05） than those of the positive control and Group 1. The drip loss of breast meat for Group 1 was the lowest, and the drip loss of thigh meat for the negative control was the highest among all treatments. The shear force for the negative control and Group 3 were higher than those of other three groups. There were no differences （P 〉 0.05） on the contents of chemical components, crude moisture, crude protein, crude fat, crude ash, and inosine acid for breast and thigh meat among all treatments. [ Conclusion] NSP complex enzymes with complete enzyme categories and high enzyme activity can improve meat quality in broilers.

Overall Performance, Carcass Yield, Meat Safety Potentials and Economic Value of Heat-Stressed Broilers Fed Diets with Balanced Electrolytes

Tropical regions across the globe are characterized by an annually prolonged hot weather conditions that showcase limiting production efficiency in livestock industry, as domesticated animals leave the zone of maximum comfort, under heat stress, with death and reduced carcass yield accompanying the subsequent alteration in body chemistry and behavior. However, pen house orientation, cooling systems, genetic modification and different dietary manipulations have been employed in poultry industry, but many of such did not account for the body’s acid-base equilibrium and the potentials of aggregate levels of dietary electrolytes in enhancing carcass yield of broilers under severe heat stress conditions. Therefore, this study was conducted to investigate the effects of different electrolyte-balanced diets on overall performance, carcass yield, meat safety potentials and economic value of heat-stressed broilers reared for five weeks. Arbor Acre broiler chicks (n = 300) were randomly allotted to diets with aggregate electrolyte balance of 210 (T1), 240 (T2), 270 (T3), 300 (T4), 330 (T5) and 360 (T6) mEq/Kg, in a completely randomised design. On day 35, birds whose weights were closest to the mean class weight were selected from each replicate pen for carcass yield assessment. Also, data on performance and cost-benefit analysis were analysed using descriptive statistics and ANOVA at α = 0.05. Electrolyte-balanced diets though contained salts that presumably could have improved satiety, yet they do not enhance appetite in heat-stressed broilers. However, dietary protein efficiency was enhanced at an electrolyte balance levels of 240 and 270 mEq/kg, which translated into increased body weight gain. Weights of primal parts of birds on 270 mEq/kg DEB were highest at 35 days. Feed cost values (per kilogram weight gain) of rations with 240 mEq/kg and 270 mEq/kg DEB were lower and showcased promising economic buoyancy to both rural and commercial poultry farmers, while ensuring a high food safety standard under tropical conditions.

Effect of dietary arginine to lysine ratios on productive performance,meat quality,plasma and muscle metabolomics profile in fast-growing broiler chickens

Background: Due to the important functions of arginine in poultry,it should be questioned whether the currently adopted dietary Arg:Lys ratios are sufficient to meet the modern broiler requirement in arginine.The present study aimed,therefore,to evaluate the effects of the dietary supplementation of L-arginine in a commercial broiler diet on productive performance,breast meat quality attributes,incidence and severity of breast muscle myopathies and foot pad dermatitis(FPD),and plasma and muscle metabolomics profile in fast-growing broilers.Results: A total of 1,170 1-day-old Ross 308 male chicks was divided into two experimental groups of 9 replicates each fed either a commercial basal diet(CON,digestible Arg:Lys ratio of 1.05,1.05,1.06 and 1.07 in each feeding phase,respectively) or the same basal diet supplemented on-top with crystalline L-arginine(ARG,digestible Arg:Lys ratio of 1.15,1.15,1.16 and 1.17,respectively).Productive parameters were determined at the end of each feeding phase(12,22,33,43 d).At slaughter(43 d),incidence and severity of FPD and breast myopathies were assessed,while plasma and breast muscle samples were collected and analyzed by proton nuclear magnetic resonancespectroscopy.The dietary supplementation of arginine significantly reduced cumulative feed conversion ratio compared to the control diet at 12 d(1.352 vs.1.401,P < 0.05),22 d(1.398 vs.1.420; P < 0.01) and 33 d(1.494 vs.1.524; P < 0.05),and also tended to improve it in the overall period of trial(1.646 vs.1.675; P = 0.09).Body weight was significantly increased in ARG compared to CON group at 33 d(1,884 vs.1,829 g; P < 0.05).No significant effect was observed on meat quality attributes,breast myopathies and FPD occurrence.ARG birds showed significantly higher plasma concentration of arginine and leucine,and lower of acetoacetate,glutamate,adenosine and proline.Arginine and acetate concentrations were higher,whereas acetone and inosine levels were lower in the breast of ARG birds(P < 0.05).Conclusions: Taken together,these data showed that increased digestible Arg:Lys ratio had positive effects on feed efficiency in broiler chickens probably via modulation of metabolites that play key roles in energy and protein metabolism.

Gas stunning with CO_2 affected meat color,lipid peroxidation, oxidative stress, and gene expression of mitogen-activated protein kinases, glutathione S-transferases,and Cu/Zn-superoxide dismutase in the skeletal muscles of broilers

Background: Meat color and lipid peroxidation are important traits related to meat quality. CO_2 concentration is a critical factor that can affect meat quality in the commercial use of gas stunning(GS). However, the effect and mechanism of CO_2 stunning on meat color and lipid peroxidation during long-term storage remain poorly studied. We aimed to study the effects of GS methods, especial y CO_2 concentration, on meat color and meat lipid peroxidation in broilers during long-term storage at 4 °C and to explore the potential mechanism of meat color change via lipid peroxidation and the inner lipid peroxide scavenging system.Methods: Eighteen broilers were sacrificed after exposure to one of the following gas mixtures for 90 s: 40% CO_2+21% O_2+ 39% N2(G40%), 79% CO_2+ 21% O_2(G79%), or no stunning(0% CO_2, control). Meat color, serum variables,enzyme activities, and the gene expression of mitogen-activated protein kinase(MAPK), nuclear factor-erythroid2-related factor 2(Nrf2), glutathione S-transferase(GST) and superoxide dismutase(SOD) were determined.(Continued on next page)Results: The concentrations of serum triiodothyronine(T3, P = 0.03) and the ratio of serum free triiodothyronine/free thyroxine(FT3/FT4, P < 0.01) were decreased, whereas levels of serum cortisol(P < 0.01) were increased in the 40%CO_2 group compared with the control group. Additionally, the thiobarbituric acid-reactive substances(TBARS)3 d(P < 0.01) and TBARS6 d(P = 0.01) in breast meat and the TBARS3 din thigh meat(P < 0.01) were increased in the40% CO_2 group compared with the control group. Serum T3 was negatively correlated with TBARS6 dboth in the breast and thigh meat(r =-0.63, P < 0.01 and r =-0.47, P = 0.05 respectively). T3/T4 was negatively correlated with TBARS6 din the breast meat and in the thigh meat(r =-0.57, P = 0.01; and r =-0.53, P = 0.03 respectively). Compared with the control group, Lightness(L*)1 d(P = 0.03) and L*9 d(P < 0.01) were increased, whereas total chromatic aberration(E*)1 d(P = 0.05) and E*3 d(P < 0.01) were decreased in the breast meat of both the G40% and G79% groups. The values of yel owness(b*)3 d(P = 0.01), b*6 d(P < 0.01) and E*6 d(P < 0.01) in the thigh meat were lower in both the G40% and G79% groups than in the control group. In the breast muscle, the m RNA levels of c-Jun N-terminal kinase 2(JNK2, P = 0.03),GSTT1(P = 0.04), and SOD1(P = 0.05) were decreased, and the m RNA levels of JNK1(P = 0.07), Nrf2(P = 0.09), and GSTA3(P = 0.06) were slightly lower in both the G40% and G79% groups compared with the control group. However, among these genes, only the m RNA level of JNK1 was decreased in the G40% group compared with the control group and the G79% group(P = 0.03) in the thigh muscle.Conclusions: Compared with the control group, meat color quality in the breast meat was decreased, and the expression of genes in the MAPK/Nrf2/ARE(antioxidant responsive element) antioxidant pathway in breast muscle was partly suppressed by GS of both 40% and 79% CO_2. However, oxidative stress and meat lipid peroxidation during storage were aggravated by GS with 40% CO_2 compared to GS with 79% CO_2 and no GS.

紫花地丁对热应激下肉鸡生长性能、肉品质和肠道菌群的改善作用

旨在评估紫花地丁(Viola yedoensis Makino,VYM)对热应激下AA肉鸡生长性能、肉品质和肠道菌群的改善作用。将60只1日龄雄性AA肉鸡随机分为6个组,分别为:对照组(NT组),高剂量紫花地丁组(NT+VYM-H组);热应激组(HS组),低、中、高剂量紫花地丁热应激组(HS+VYM-L、HS+VYM-M和HS+VYM-H组,紫花地丁添加量分别为0.5%、1.5%、4.5%),2~42 d,热应激组肉鸡暴露于高温中,紫花地丁组全程饲喂添加相应剂量紫花地丁的日粮。所有肉鸡均在42日龄时屠宰,对生长性能、血清生化指标、肉品质、十二指肠形态、酶活性相关基因表达水平以及肠道菌群组成等进行检测。结果显示,在热应激条件下,与热应激组相比,1.5%紫花地丁组肉鸡29~42 d平均日增重显著升高,料重比显著降低(P<0.05);热应激条件下,添加紫花地丁显著降低肉鸡35 d血清HSP70水平(P<0.05),添加0.5%紫花地丁显著提高十二指肠脂肪酶活性(P<0.05),与肉鸡胸肌生肌因子相关的Pax3、Pax7、Myog、Myod、Myf5 mRNA表达显著上调(P<0.05),与十二指肠消化吸收功能相关的Pparα、Fatp1、B^(0)at1、Pept1、Cat1、Eaat3 mRNA表达显著上调(P<0.05);在热应激条件下,添加1.5%的紫花地丁显著降低了肉鸡的肌肉剪切力、肉色(P<0.05);盲肠中,紫花地丁显著提高了肠道菌群的丰富度和多样性(P<0.05),在门水平上,增加了拟杆菌门的丰度,且与肌肉pH(45 min)呈显著正相关;属水平上,降低了Subdoligranulum属丰度,且与十二指肠淀粉酶活性呈显著负相关。综上,在本试验条件下,日粮中补充1.5%和4.5%紫花地丁可有效减轻热应激导致的肉鸡生长性能和肉品质的降低,并能够调节其肠道菌群的平衡。本研究为紫花地丁在肉鸡生产中的应用提供了科学依据,对家禽养殖临床中热应激的防治具有参考意义。

大豆活性肽对黄羽肉鸡生长性能、屠宰性能、肉品质、免疫功能及抗氧化能力的影响

本文旨在研究大豆活性肽对黄羽肉鸡生长性能、屠宰性能、肉品质、免疫功能及抗氧化能力的影响。选用1日龄健康大恒黄羽肉鸡公鸡800只,随机分成5组,每组10个重复,每个重复16只鸡。对照组饲喂基础饲粮,抗生素组饲喂基础饲粮+0.2 g/kg恩拉霉素,试验组分别饲喂以0.2%、0.4%、0.6%的大豆活性肽替代基础饲粮中豆粕的试验饲粮。试验期70 d。结果表明:1)抗生素组和0.2%大豆活性肽组的末重、平均日增重显著高于对照组(P<0.05),料重比显著低于对照组(P<0.05)。各组之间平均日采食量无显著差异(P>0.05)。2)各组之间屠宰率、全净膛率、半净膛率、胸肌率、腿肌率和腹脂率无显著差异(P>0.05)。3)各组之间血常规指标无显著差异(P>0.05)。4)0.2%大豆活性肽组的胸肌45 min肉色显著高于对照组、抗生素组和0.4%大豆活性肽组(P<0.05)。各组之间胸肌45 min和24 h pH、24 h肉色、滴水损失、蒸煮损失以及肌纤维直径、横截面积和密度无显著差异(P>0.05)。5)抗生素组和0.2%、0.4%、0.6%大豆活性肽组的血清溶菌酶含量显著高于对照组(P<0.05)。0.2%大豆活性肽组的血清白细胞介素-1β(IL-1β)和干扰素-γ(IFN-γ)含量显著低于对照组(P<0.05),血清白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、免疫球蛋白G(IgG)、免疫球蛋白A(IgA)和免疫球蛋白M(IgM)含量显著高于对照组(P<0.05)。6)各组之间脾脏指数和法氏囊指数无显著差异(P>0.05)。7)抗生素组和0.2%大豆活性肽组的血清总抗氧化能力(T-AOC)显著高于对照组(P<0.05)。各组之间血清谷胱甘肽过氧化物酶(GSH-Px)和总超氧化物歧化酶(T-SOD)活性无显著差异(P>0.05)。由此可见,饲粮中添加0.2%大豆活性肽可提高黄羽肉鸡生长性能和免疫功能,改善肉品质和增强机体抗氧化能力,且具有替代抗生素的作用。

发酵饲料对肉鸡生长性能及经济效益的影响

试验旨在研究发酵饲料对肉鸡生长性能、肉品质及经济效益的影响。试验选择1 600只AA肉鸡分成4组,每组4个重复,每个重复100只肉鸡。对照组饲喂基础饲粮,试验组分别在基础饲粮中添加2.5%、5.0%及10.0%发酵饲料。试验期42 d。结果显示:与对照组相比,22~42日龄,5.0%组和10.0%组42日龄体重、平均日增重及平均日采食量显著升高(P<0.05),料重比显著降低(P<0.05);1~42日龄,5.0%组和10.0%组的平均日增重及平均日采食量显著升高(P<0.05),料重比显著降低(P<0.05),5.0%组和10.0%组肌肉pH24 h值、L*值、b*值及蒸煮损失显著降低(P<0.05),2.5%组、5.0%组和10.0%组肌肉剪切力显著降低(P<0.05),5.0%组和10.0%组肌肉中甘氨酸、肌苷酸含量显著升高(P<0.05)。2.5%组、5.0%组和10.0%组的增重收益分别比对照组提高了2.55%、8.74%、12.26%,养殖利润分别提高了2.69%、11.73%、13.15%。研究表明,肉鸡饲喂适量的发酵饲料可以提高生长性能,改善肉品质,增加养殖利润,饲喂5%~10%的发酵饲料较为适宜。

混合冷却对宰后黄羽肉鸡能量代谢和品质的影响

目的:探究混合冷却(水冷加风冷)过程中,低温风冷对黄羽肉鸡能量代谢和品质的影响。方法:处理组先后采用水冷处理(0~4℃)后风冷处理(-8、-18、-25℃和-31℃);对照组分别为传统水冷组(0~4℃)和传统混合冷却组(水冷处理(0~4℃)后进行风冷处理组(0~4℃))。最终统一将85日龄黄羽肉鸡胴体中心温度降低到4℃,通过测定降温速率、pH值、能量代谢和品质指标,确定最佳风冷温度。结果:风冷温度为-25℃和-31℃处理的降温时间分别为2 537 s和2 272 s,与传统水冷相比分别缩短了27.78%和35.33%;与传统混合冷却相比分别缩短了51.87%和56.90%。风冷温度为-25℃和-31℃处理延缓了肌肉p H值下降、降低了肌肉的滴水损失和蒸煮损失,与对照组相比剪切力显著升高、不易流动水含量显著增加(P<0.05)。风冷温度为-25℃和-31℃处理的肌肉己糖激酶、磷酸甘油酸激酶和乳酸脱氢酶活性比其他组低,并且腺嘌呤核苷三磷酸(adenosine triphosphate,ATP)和糖原消耗最少,乳酸和单磷酸腺苷(adenosine monophosphate,AMP)产生最少,AMP/ATP最小(P<0.05)。以上研究表明-25℃和-31℃风冷温度显著抑制了宰后初期鸡肉的无氧糖酵解反应速率,延缓了p H值下降速率,有效改善了肌肉持水力。结论:从工业生产节能的角度,确定-25℃为风冷处理的最佳温度。

黄羽肉鸡肉质研究进展

随着国内经济的高速发展,消费者对肉类的品质、新鲜度、风味要求日益提高。黄羽肉鸡因肉质细嫩、滋味鲜美,富含人体生长发育所需的营养物质,在国内肉鸡市场占据重要位置。通常采用肉色、pH、嫩度和系水力等物理指标评定肉品优劣。肉品的风味也是消费者选购时的关注重点,风味包括肉品中氨基酸、脂肪酸、肌苷酸等风味前体物质在高温加热下经过化学反应产生的可溶性滋味化合物和挥发性香气化合物。文章从肉质的物理评定指标以及风味前体物质角度简述了我国黄羽肉鸡肉质研究进展,分析了挥发性香气化合物对肉质的影响,为探究鸡肉风味的调控机制以及肉质改良提供理论基础和研究思路。

不同水平餐桌剩余食物对肉鸡后期生长、免疫及肉质性状的影响

【目的】本试验通过研究添加不同比例餐桌剩余食物(RPL)对肉鸡后期生长性能、屠宰性能、肉质性状、免疫器官指数及血清生化指标的影响,旨在为RPL减量替代玉米豆粕和在肉鸡养殖中的应用提供数据支持。【方法】选择1日龄白羽肉仔鸡公鸡504只,随机分为4组,每组6个重复,每个重复21只鸡。试验前期(第1~21天)饲喂相同饲粮;后期(第22~42天)设计4种饲粮,对照组饲喂玉米-豆粕基础饲粮,试验组分别饲喂添加10%、20%和30%RPL的饲粮(1/2 RPL替代玉米,1/2 RPL替代豆粕)。测定肉鸡后期生长性能,42日龄屠宰后测定屠宰性能、肉质性状、免疫器官指数及血清生化指标。【结果】与对照组相比,(1)添加10%、20%RPL对肉鸡生长性能影响不显著(P>0.05),添加30%RPL显著降低平均体重、平均日采食量、平均日增重(P<0.05),极显著提高料重比(P<0.01)。(2)添加10%、20%RPL对肉鸡屠宰率、全净膛率、胸肌率和腿肌率均无显著影响(P>0.05),但添加30%RPL显著降低胸肌率(P<0.05)。(3)饲粮中添加不同比例RPL对肉鸡免疫器官指数无显著影响(P>0.05),10%、20%RPL组肉鸡血清免疫球蛋白G(IgG)含量显著升高(P<0.05),30%RPL组血清超氧化物歧化酶(SOD)活性显著降低(P<0.05)。(4)添加不同比例RPL对肉鸡胸肌和腿肌肉色、24、48和72 h滴水损失、酸度、蒸煮损失及剪切力均无显著影响(P>0.05)。【结论】在肉鸡饲粮中添加10%~20%RPL对肉鸡后期生长性能、屠宰性能、肉质性状、免疫器官指数、血清生化指标等均无负面影响;RPL可替代常规饲粮中的玉米和豆粕在肉鸡养殖后期中应用。

不同油脂来源及添加水平对肉鸡颗粒饲料质量、生长性能和肉品质的影响

本试验旨在研究不同油脂来源及添加水平对肉鸡颗粒饲料质量、生长性能、肉品质及血清生化指标的影响。试验选取1日龄白羽肉鸡960只,随机分为6组,每组8个重复,每个重复20只鸡。采用双因素试验设计,饲粮中油脂来源分别为大豆油、膨化大豆和脂肪粉,油脂添加水平分别为3%和5%。试验期42 d,分为前期(1~21日龄)和后期(22~42日龄)2个阶段。结果表明:1)在颗粒饲料质量方面,脂肪粉组成型率、颗粒耐久性和硬度显著高于其他2组(P<0.05);相比于3%添加水平,5%添加水平显著降低了颗粒饲料成型率、颗粒耐久性和硬度,且除脂肪粉组外,豆油组和膨化大豆组颗粒饲料颗粒耐久性显著降低(P<0.05),并均低于90%。2)在肉鸡生长性能方面,与大豆油组相比,5%脂肪粉组前期料重比显著降低(P<0.05);膨化大豆组后期和全期平均日增重显著降低(P<0.05)。3)在肉品质和血清生化指标方面,与大豆油组相比,脂肪粉组肉鸡胸肌剪切力和24 h滴水损失显著降低(P<0.05),膨化大豆组胸肌24 h滴水损失显著降低(P<0.05);膨化大豆组和脂肪粉组血清三碘甲状原氨酸(T3)含量和T3/甲状腺素(T4)值显著提高(P<0.05)。相比于3%添加水平,5%添加水平显著降低了肉鸡胸肌剪切力(P<0.05)。综上所述,添加5%脂肪粉能够提高肉鸡颗粒饲料质量、肉品质以及甲状腺的功能活性。

日粮添加生物法苹果酸在中试条件下对肉鸡生产的影响

本试验旨在评估生物法苹果酸产品在肉鸡大群试验中的促生长和肉质改善效果,为生物法苹果酸在肉鸡饲粮中的推广应用提供数据支撑。选用1000只1日龄的爱拔益加肉仔鸡公雏,随机分为2个处理,每个处理10个重复,每个重复50只鸡。对照组饲喂玉米-豆粕型基础日粮,处理组在基础日粮中添加0.8%生物法苹果酸。试验持续42 d。结果表明:日粮添加0.8%生物法苹果酸对肉鸡采食量、死淘率无显著影响(P> 0.05),但能通过增加试验后期(22~42 d)平均日增重(7.53%)(P=0.001)和降低料重比(4.47%)(P=0.002)有效增加肉鸡42 d出栏重(4.93%)(P <0.001);在屠宰性能和肉品质方面,日粮添加苹果酸对全净膛率、胸肌率、腿肌率、腹脂率、胸肌肉色和pH均无显著影响(P> 0.05),但能显著降低胸肌肉的滴水损失(11.31%)(P <0.001)。日粮添加0.8%苹果酸可以在中试条件下有效提高肉鸡的生长性能,增强鸡肉保水性,改善肉品质。因此,本研究推荐生物法苹果酸作为饲料添加剂,在集约化养殖的背景下应用于肉鸡饲粮。

添加牛樟芝多糖和锌对麻黄肉鸡屠宰性能、肉品质及肌肉抗氧化能力的影响

本研究旨在探究饲粮中添加牛樟芝多糖和锌对麻黄肉鸡生长性能、屠宰性能及肌肉品质、抗氧化能力的影响,为牛樟芝多糖和锌在肉鸡生产中的应用提供理论依据。选取35日龄健康的麻黄肉鸡公鸡180羽,随机分为如下3组:饲喂基础饲粮的对照、饲喂添加500 mg/kg牛樟芝多糖(ACP)的基础饲粮组(ACP处理)、饲喂添加500 mg/kg牛樟芝多糖+100 mg/kg锌的基础饲粮组(ACP+锌处理),每组设6个重复,每个重复设10羽鸡。试验期为28 d,其间记录鸡的生长性能相关指标;63日龄时,每个重复分别选取1~2羽鸡屠宰、采样,测定与屠宰性能、肉品质及肌肉抗氧化性能相关的指标。结果显示,与对照相比,ACP、ACP+锌处理胸肌在屠宰后45 min测量所得pH值(pH45 min值)显著升高(P<0.05),且滴水损失率显著降低(P<0.05)。与对照、ACP+锌处理相比,ACP处理胸肌的咀嚼性显著升高(P<0.05)。与对照相比,ACP、ACP+锌处理胸肌中的丙二醛含量均显著降低(P<0.05)。由结果看出,在饲料中单独添加牛樟芝多糖或联合添加牛樟芝多糖+锌均可以减少肉鸡胸肌的滴水损失,调节其pH值,提高肌肉品质和肉鸡胸肌的抗氧化能力。

西洋参加工副产物对黄羽肉鸡血清生化指标、抗氧化能力和肉品质的影响

为研究西洋参加工副产物对黄羽肉鸡血清生化指标、抗氧化能力及肉品质的影响。本试验选择7日龄黄羽肉鸡160只,随机分成4组,每组4个重复,Ⅰ组、Ⅱ组、Ⅲ组分别添加1%、3%、5%西洋参加工副产物,Ⅳ组为基础饲粮对照组,试验期100d。结果表明,西洋参加工副产物可显著降低肉鸡血糖含量(P <0.05),并显著降低血清中低密度脂蛋白含量(P <0.05);试验组总抗氧化力和谷胱甘肽过氧化物酶极显著高于对照组(P <0.01);Ⅰ组和Ⅱ组的胸肌、腿肌pH值、亮度、红度和黄度极显著优于对照组(P<0.01);试验组胸肌滴水损失和剪切力显著优于对照组(P <0.05)。在本试验条件下,饲粮中添加1%~3%的西洋参加工副产物,能够较好的调节胸肌、腿肌外观色泽,更符合市场消费的需求。

高粱替代玉米对颗粒饲料质量和肉鸡生长性能、屠宰性能、肉品质及营养物质表观消化率的影响

本试验旨在研究高粱替代玉米对颗粒饲料质量和肉鸡生长性能、屠宰性能、肉品质及营养物质表观消化率的影响。本试验以960只1日龄爱拔益加(AA)肉鸡为研究对象,将其随机分成6组,每组8个重复,每个重复20只鸡。试验分为饲养前期(1~21日龄)和后期(22~42日龄)2个阶段。对照组饲喂不添加高粱的常规玉米-豆粕型饲粮,试验组饲喂以高粱分别替代常规玉米-豆粕型饲粮中20%、40%、60%、80%和100%玉米的试验饲粮。结果显示:1)在颗粒饲料质量方面,随着高粱替代玉米比例的增加,颗粒饲料的成型率总体呈上升趋势,但各组间无显著差异(P>0.05);颗粒饲料的颗粒耐久性(PDI)呈先降低后升高的趋势,且均高于90%;颗粒饲料的硬度、淀粉糊化度以及亮度(L^(*))、红度(a^(*))和黄度(b^(*))值均持续降低。20%替代组与对照组在颗粒饲料成型率、硬度、PDI及色泽方面均无显著差异(P>0.05)。2)在肉鸡生长性能方面,随着高粱替代玉米比例的增加,肉鸡各阶段的末重、平均日采食量、平均日增重及死淘率均呈下降趋势,料重比呈上升趋势。20%替代组与对照组相比,肉鸡各阶段的平均日增重、平均日采食量和料重比均无显著差异(P>0.05)。3)在屠宰性能、肠道指数和肉品质方面,各组肉鸡的屠宰性能指标、各肠段相对长度和相对重量以及腿肌和胸肌的L*和a*值均无显著差异(P>0.05)。4)在营养物质表观消化率方面,随着高粱替代玉米比例的增加,饲养前期和后期的粗蛋白质和干物质表观消化率均呈下降趋势,在饲养后期20%替代组与对照组粗蛋白质和干物质表观消化率差异不显著(P>0.05)。综上所述,综合考虑高粱替代玉米对颗粒饲料质量以及肉鸡生长性能、屠宰性能、肠道发育、肉品质及营养物质表观消化率的影响,建议肉鸡饲粮中高粱替代玉米比例在前期不超过20%,在后期不超过60%。