Effect of dietary high-oleic acid sunflower seed, palm oil and vitamin E supplementation on broiler performance, fatty acid composition and oxidation susceptibility of meat

1. A study was conducted to evaluate the effect of inclusion of two fat sources: high-oleic acid sunflower seed (HOASS; 0, 50, 100, 150 and 200 g/kg diet) and palm oil (PO), and dietary supplementation of vitamin E (alpha-tocopheryl acetate, 200 mg/kg diet) on performance, fatty acid composition and susceptibility to oxidation of white and dark chicken meat during refrigerated storage. Female chicks (3 to 6 weeks) were given one of 5 diets containing 90 g/kg of added fat with increasing monounsaturated fatty acid (MUFA) content, adjusted by progressively replacing PO by HOASS. 2. Body weight gain and gain:food ratio of birds were depressed in diets containing the highest proportions of HOASS (150 and 200 g/kg). Relative abdominal fat was reduced in birds fed diets including HOASS, except in the diet containing 100 g HOASS/kg. The inclusion of alpha-tocopheryl acetate improved body weight gain and gain:food ratio. 3. According to the fatty acid profile of the diets, saturated and polyunsaturated fatty acid (SFA and PUFA, respectively) contents were significantly reduced and MUFA content was significantly increased in white and dark chicken meats when the saturated oil, PO, was replaced progressively by HOASS in the diet. The inclusion of alpha-tocopheryl acetate increased PUFA content in both meats. 4. After 4 and 7 d of refrigerated storage, white and dark meat samples obtained from birds fed on diets containing HOASS had significantly lower thiobarbituric acid reacting substance (TBARS) values than those derived from the PO diet. The addition of alpha-tocopheryl acetate significantly reduced the lipid oxidation in white and dark meat. 5. Overall, the results showed that increasing MUFA content of chicken meat by replacing dietary PO with HOASS (up to 100 g/kg) did not adversely affect broiler performance and reduced the susceptibility of meat to oxidation during refrigerated storage. Dietary alpha-tocopherol supplementation improved chicken performance and was effective in protecting lipid meat from oxidation.     

Food intake, growth rate, food conversion and food choice in broilers fed on diets high in rapeseed meal and pea meal, with observations on sensory evaluation of the resulting poultry meat

1. Experiments were done to measure the effects of 100 and 200 g/kg of either pea meal or low glucosinolate, low erucic acid rapeseed meal on food intake and growth, food choice and meat organoleptic quality in broiler chickens. 2. The test diets were formulated to be iso-energetic and iso-nitrogenous with a soy-wheat control diet. In all diets, lysine was fixed at 11.0 g/kg and all other indispensable amino acids were present in excess of requirements. 3. Food intake was little affected by the inclusion of 100 g/kg of pea meal in the diet but 200 g/kg of peas caused a decrease. Rapeseed produced a decrease in food intake at both dietary concentrations. 4. Weight gain was similarly affected, but food conversion from d 0 to d 42 was little affected by the inclusion of either peas or rapeseed. 5. Absolute breast muscle weight was affected by diet but there was no significant difference in breast weight as a proportion of total body weight. 6. From d 7 onwards, selection against the pea-containing diet approached statistical significance. Between d 7 and d 14, birds ate almost twice as much of the control as of the pea-containing diet. Birds offered a rapeseed meal diet ate similar amounts of that and the control diet. 7. The breast meat from birds given 200 g rapeseed/kg was the only meat identified as different but no strong aversion was expressed by the tasting panel.     

Direct supplementation of diet is the most efficient way of enriching broiler meat with n-3 long-chain polyunsaturated fatty acids

1. Concentrations of beneficial omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs) in poultry meat can be improved by increasing the concentration of n-3 PUFA in poultry diets.

2. A decrease in flavour quality is, however, usually associated with the dietary supplementation with n-3 PUFA, which is due to the susceptibility of PUFA to oxidation.

3. This experiment was conducted to study the effects of introducing two different n-3 fatty acid sources (extruded linseed and DHA Gold?, a proprietary algal product rich in docosahexaenoic acid), either separately or together, on broiler productive performance, and meat quality, oxidative stability, sensory traits and LC-PUFA profile.

4. Birds given the algal product displayed better productive performances than animals from other groups.

5. The data revealed an improvement in the fatty acid nutritional value of meat from birds receiving the algal product and an inefficient conversion of α-linolenic acid (LNA) into LC-PUFA.

6. Metabolisation of LNA in vivo is not sufficient to improve meat quality in n-3 LC-PUFA and direct supplementation of the diet with n-3 LC-PUFA is a better alternative to modulate an increase in beneficial fatty acids of broiler meat.

7. The overall acceptability of meat was negatively affected by the dietary supplementation with 7.4% of DHA, in contrast to the supplementation with 3.7% of DHA, which showed to be efficient in improving LC-PUFA meat content without affecting its sensory properties.     

亚麻籽对鸡蛋中脂肪酸富集及蛋品质的影响

本试验旨在探讨日粮中亚麻籽添加水平和添加时间对蛋中n-3多不饱和脂肪酸的富集以及蛋品质的影响。选取46周龄京粉1号蛋鸡1 344只,随机分为4个组,每组6个重复,每个重复56只。4个处理组日粮中亚麻籽的添加水平分别为0%(对照组)、5%、10%、15%。试验期60 d。试验第10、20、30、45、60天测定蛋中α-亚麻酸、二十碳五烯酸(EPA)、二十二碳六烯酸(DHA)等n-3多不饱和脂肪酸(n-3PUFA)含量。第30、60天测定蛋壳强度、蛋黄色度和哈氏单位。结果表明:亚麻籽的添加水平、时间以及二者互作均对蛋中n-3PUFA的富集产生显著影响,蛋中n-3PUFA含量随着亚麻籽添加水平和添加时间增加呈上升趋势,随后达到稳定;5%亚麻籽组中鸡蛋DHA含量最高,其他脂肪酸含量以15%亚麻籽组最高;蛋中EPA含量在20 d达到最高,其他脂肪酸在30 d达到最高;蛋黄色度随着日粮中亚麻籽添加水平升高而显著降低,其他蛋品质指标无显著变化。由此表明,给蛋鸡饲喂含15%亚麻籽日粮30 d以上,可获得理想n-3PUFA富集鸡蛋,但要保证日粮色素水平稳定。     

不同屠宰活重豫西黑猪的营养成分及肉质特性分析

【目的】探讨豫西黑猪营养成分及肉质性状在不同体重阶段的发育性变化规律。【方法】选取平均体重约为60、75、90、105、120 kg 5个体重阶段的豫西黑猪,每组5头,共25头,每组随机选取3头进行屠宰,公母随机。屠宰后取背最长肌测定眼肌面积、背膘厚、脂肪率、失水率、脂肪酸、氨基酸和胆固醇等指标,测定肌内脂肪含量、脂滴直径和脂滴数目,采集100 g腰大肌测定熟肉率。【结果】豫西黑猪在体重达到120 kg之前,随着屠宰活重的增加,眼肌面积、背膘厚、脂肪率、熟肉率、肌内脂肪含量、肉色、剪切力、脂滴数目和脂滴直径均随之增加。眼肌面积在105、120 kg时均极显著高于60、75 kg(P<0.01),显著高于90 kg(P<0.05);背膘厚在90、105、120 kg时均极显著高于60 kg(P<0.01);肌内脂肪含量在90、105、120 kg时均显著高于60、75 kg(P<0.05);脂滴直径和脂滴数目在75、90、105、120 kg时均显著高于60 kg(P<0.05);脂肪酸中饱和脂肪酸以肉豆蔻酸、棕榈酸、硬脂酸等为主,不饱和脂肪酸以棕榈油酸、油...     

Sensorial quality and bone strength of female and male broiler chickens are influenced by weight and growth rate

1. An experiment was conducted with 98 male and 98 female broiler chickens (Ross 308) to study the effect of growth rate, induced by different dietary means, sex and live weight (1500?g and 2000?g) at slaughter on production parameters, bone strength and sensorial characteristics of the breast meat.

2. The birds were divided into four groups and individually fed a standard commercial diet, a high energy diet or low energy diet from d?11 to slaughter at between d 28 and 39. Three groups were fed ad libitum and a further group was fed a restricted amount of the high energy feed. Half of the birds in each group were slaughtered at approximately 1500?g and the other half at 2000?g live weight.

3. The diets resulted in different growth rates. The chickens fed the high energy and the commercial diet had the highest growth rate at both live weights at slaughter. The restricted fed chickens had lower bone strength than the chickens fed the low energy diet.

4. Breast meat from male broilers was juicer, more tender and less hard than breast meat from females. Chickens slaughtered at 2000?g live weight were juicer than those slaughtered at 1500?g. Chickens given the high energy feed ad libitum and restricted had different growth rates, but the sensory parameter related to texture showed no difference.

5. It was concluded that an increased slaughter weight might improve meat quality due to improved juiciness.     

Comparison of effects of dietary olive oil,tallow and vitamin E on the quality of broiler meat and meat products

1. The effect of dietary fat and vitamin E supplementation on quality attributes (drip loss, oxidative stability, sensory quality) in chicken meat and meat products was investigated. Broiler chicks were fed on diets containing tallow (60 g/kg) or olive oil (60 g/kg) at a basal (30 mg/kg diet) or supplemental (200 mg/kg diet) concentration of alpha-tocopheryl acetate for 8 weeks. The alpha-tocopherol content and fatty acid composition of breast and thigh meat was determined. Drip loss was determined in breast fillets. Lipid oxidation (thiobarbituric acid-reacting substances/TBARS) and sensory quality (warmed-over flavour development/WOF) were assessed in minced thigh meat during storage. 2. Dietary olive oil increased the ratio of monounsaturated to saturated fatty acids (MUFA/SFA) in the diets. In breast and thigh, this resulted in approximately a two-fold increase in the MUFA/SFA ratio. Supplemental alpha-tocopherol increased the alpha-tocopherol content of muscles. 3. Dietary fat did not influence drip loss in thawed breast fillets during refrigerated storage, but supplemental alpha-tocopherol reduced drip loss. 4. TBARS and WOF development in minced thigh meat patties were also reduced by supplemental alpha-tocopherol following frozen storage, or cooking and refrigerated storage. Storage stability was not adversely affected by dietary fat. 5. Overall, the results showed that increasing the monounsaturated profile of chicken meat lipids did not adversely affect quality characteristics. Dietary alpha-tocopherol supplementation was a more important factor in the determination of broiler meat quality.     

Comparison of the utilisation of palm kernel meal,brewers' dried grains and maize offal by broiler chicks

1. Palm kernel meal (PKM), brewers dried grains (BDG) and maize offal (MO) were included in broiler diets, each at 100, 150 or 200 g/kg; the diets were fed up to 35 d of age. 2. Overall food intake and weight gain decreased in the order BDG, PKM and MO. There were, however, significant interactions between the test ingredients and dietary concentrations in all the growth responses. Food intakes increased with the dietary concentrations of each test ingredient, but the increase was greater for BDG than PKM or MO. For weight gain, at 100 g/kg, the final body weights of the chicks fed on the diets with BDG and MO were similar, and those of chicks fed on the diet with PKM slightly lower. However, at 200 g/kg, growth rate of chicks fed on the BDG and PKM diets were similar while those of chicks fed on the MO diet was 7% lower. Efficiency of food utilisation was similar at 100 g/kg for all the ingredients and decreased as their concentrations increased; however, the decrease was considerably less for the PKM than for the MO and BDG diets. 3. Broilers fed on the BDG-based diets voided most excreta followed by those fed on the PKM and MO diets; excreta water content was highest from birds fed on the MO diets followed by the PKM and BDG diets. Apparent retention of dry matter was similar with all the test ingredients, but it decreased only significantly at 200 g/kg dietary concentration. The rate of passage was faster with the PKM diets followed by the MO and BDG diets; it was increased at 200 g/kg dietary concentration of the test ingredients.     

Effects of dietary rosemary, rosemary volatile oil and vitamin E on broiler performance, meat quality and serum SOD activity

1. The current study was conducted to evaluate the effects of dietary supplementation with vitamin E (as alpha-tocopherol acetate), dried rosemary leaves and rosemary volatile oil on the performance, meat quality (measured as sensory variables, pH, colour, malondialdehyde (MDA) level, and bacteria count) and serum superoxide dismutase (SOD) activity in broilers fed on maize-soybean meal based diets. 2. A total of 800 broiler chicks were randomly allocated to 8 dietary treatments, which were set up with 1 control group and 7 experimental groups. The control group (VitE1) was given a basal diet including 50 mg/kg alpha-tocopherol acetate, while the experimental groups were given 5 x 7 g/kg rosemary plant (R1), 8 x 6 g/kg plant (R2), 11 x 5 g/kg plant (R3), 100 mg/kg plant oil (RO1), 150 mg/kg plant oil (RO2), 200 mg/kg plant oil (RO3) or 200 mg/kg alpha-tocopherol acetate (VitE2). 3. Although there were no statistical differences observed for feed consumption, other performance variables including live weight gain, feed efficiency and carcase yield were significantly affected. The addition of rosemary volatile oil had more effect on the performance variables than did the rosemary plant itself. 4. As a measure of meat shelf life, TBA analyses were performed on the meat samples on d 1, 3 and 5 after culling. Meat MDA levels of groups fed diets with rosemary and rosemary volatile oil were significantly lower than that of groups fed diets containing alpha-tocopherol acetate alone. 5. Significant differences were also seen between the control and experimental groups for meat colour and meat pH values as well as for sensory analyses. 6. Microbiological analyses conducted at the end of the experiment showed that E. coli counts were significantly reduced in meat samples from the experimental groups. 7. In conclusion, dietary supplementation with rosemary and its volatile oil improved broiler meat quality. Moreover growth performance was positively affected by the rosemary volatile oil supplementations.     

Lack of interrelationship between the effects of dietary factors and food withdrawal on carcase quality of broiler chickens

1. Four factorial experiments were carried out to determine whether there is any interrelationship between dietary energy-to-protein (E:P) ratio (experiments 1, 2 and 3) or pelleting the diet (experiment 4) and the duration of food withdrawal (FW), in their effect on carcase quality of broiler male chickens. The quality was evaluated by yields of carcase and breast meat, abdominal fat pad size, and the content and composition of the fat in the meat. The effect of sex on the response to FW was also determined in experiment 3 and that of age in experiment 4. 2. The diet with an E:P ratio higher than recommended decreased the weights of carcase and breast meat significantly (P 0.05) in 2 of the 3 experiments, and consistently increased the size of the abdominal fat pad and the fat content in thigh, but not in breast meat. Abdominal fat pad and the fat in meat of birds fed on this diet contained a significantly higher amount of oleic acid and a lower amount of linoleic acid, than the fat of birds fed on the diets with the recommended and the low E:P ratios. The pellets increased significantly the weights of carcase and breast meat and the relative size of abdominal fat pad. 3. FW for 24 h decreased significantly the weight at slaughter in all 4 experiments, carcase weight in 3 experiments, and breast weight in 1 experiment. However, it did not affect the relative size of the abdominal fat pad, the fat content in thigh and breast meat, and the composition of fatty acids in these tissues and in abdominal fat. None of the variables mentioned was affected significantly by the interaction between the dietary factors evaluated, sex or age of the birds on the one hand, and FW on the other hand. 4. It is concluded that the effect of 24 h of FW on weight at slaughter, carcase and breast meat weights and on fattening, is not affected by dietary E:P ratio, pelleting the diet, or sex and age of the broilers.     

Effect of dietary flaxseed, flax oil and n-3 fatty acid supplement on hepatic and plasma characteristics relevant to fatty liver haemorrhagic syndrome in laying hens

1. Two experiments were carried out to investigate the effect of dietary flaxseed, flax oil and n-3 fatty acid supplementation (Dry n-3) on hepatic fat content, plasma triglycerides, hepatic haemorrhage score, egg production, food intake and body weight in an inbred line of Single Comb White Leghorns (UCD-003) predisposed to fatty liver haemorrhagic syndrome (FLHS) and normal SCWL hens. 2. Feeding diets containing 100 g/kg ground flaxseed, 40 g/kg flax oil, or 100 g/kg Dry n-3 reduced body weight and significantly reduced hepatic fat content compared to feeding the control diet with animal and vegetable oil as a fat source. 3. Hepatic malondialdehyde, an indicator of lipid peroxidation within the liver, was not significantly affected by dietary treatment. 4. Normal SCWL hens tended to have higher egg production, greater body weight, greater food intake and higher blood triglyceride concentrations than UCD-003 hens, although the strain effects were not significant. Liver weight as a percent of body weight was significantly lower in normal SCWL hens. Treatments by strain interactions were not found. 5. The result suggested that dietary flaxseed, flax oil and Dry n-3 decrease hepatic fat content and reduce body weight, 2 of the predisposing factors believed to contribute to FLHS onset. However, haemorrhages were still apparent in both strains regardless of treatment, indicating that other unknown underlying mechanisms may also be responsible for FLHS.     

Influence of extruded linseed on growth, carcass composition, and meat quality of slaughtered pigs at one hundred ten and one hundred sixty kilograms of liveweight

The Western diet is characterized by a high intake of SFA relative to PUFA, and the consumption of n-3 PUFA is decreased relative to n-6 PUFA. Therefore, there has been much interest in recent years in ways to manipulate the fatty acid composition of meat. The objective of this work was to determine the effects of dietary extruded linseed, an n-3 PUFA source, on growth performance, carcass composition, meat quality, and oxidative stability of pigs slaughtered at 111.0 (+/-4.8) kg of BW and 160.0 (+/-9.2) kg of BW. The association of these factors with BW at slaughter was also examined. Forty barrows, 78.1 (+/-1.75) kg of initial BW, were fed a control diet (2.5% sunflower oil) or a linseed diet containing 5% of whole extruded linseed. Both diets contained 170 mg of vitamin E and 250 mug of selenium. Eight pigs from each dietary treatment were slaughtered at 110 kg of BW and the others at 160 kg of BW. There was no dietary effect (P > 0.05) on growth, carcass characteristics, meat quality, or the activity of malic enzyme in LM and backfat. Inclusion of linseed increased (P < 0.05) n-3 PUFA content in both LM and backfat and decreased the n-6:n-3 PUFA ratio from 12 to 4.5 in LM, and from 11 to 3 in backfat. Liveweight at slaughter significantly influenced carcass characteristics, meat quality, total lipid and oxidative stability of LM, malic enzyme activity in adipose tissue, and fatty acid content of LM and backfat. This study shows that the inclusion of linseed in swine diets may improve the fatty acid profile of pork without deleteriously affecting oxidation or color stability. Thus, such a feeding practice may improve human health based on the n-6:n-3 PUFA ratio recommended for the human diet.     

Comparison of grain sources for swine diets and their effect on meat and fat quality traits

A study was conducted to evaluate the effect of dietary grain sources on various compositional and quality characteristics of pork from pigs reared in a commercial environment. Pigs were fed 1 of 5 dietary treatments containing the following single or blended grain sources throughout most of the grow-finish period: 1) yellow corn, 2) white corn, 3) 1/3 yellow corn and 2/3 white corn, 4) 2/3 yellow corn and 1/3 white corn, and 5) barley. Pigs were from 2 sire genetic types, Duroc and Hampshire x Duroc, mated to PIC 1055 females. A total of 1,040 pigs were included in the study in a 2 x 2 x 5 factorial arrangement with 2 genetic types, 2 sexes (barrows and gilts), and 5 dietary treatments. Eight pigs were randomly selected from each pen of 26 (n = 320) for meat and fat quality evaluation. Pigs were 27.6 kg at the beginning of the experiment and were fed to 130.2 kg. All animals were held overnight at a commercial abattoir before slaughter. One whole, skin-on, boneless loin was collected from each carcass and held at -1 degrees C in a cryovac-sealed bag at the Iowa State University Meat Laboratory. At 25 to 27 d postslaughter, loins were evaluated for meat and fat quality. Dietary treatment had no effect (P > 0.05) on 24-h pH, sensory tenderness, sensory chewiness, Instron tenderness, loin purge, or cook loss. At 25 to 27 d postslaughter, pigs fed diet 4 had a greater (P < 0.05) loin pH than pigs fed diet 1, and diets 2, 3, and 5 were not different from all treatment means. Pigs fed diet 4 had a greater (P < 0.05) Japanese color score than pigs fed diets 2, 3, and 5, and diet 1 was not different from all treatment means. Pigs fed diet 3 had a greater percentage of intramuscular fat than pigs fed diets 1 and 2, although diets 1, 4, and 5 and diets 1, 2, and 5 were not different (P > 0.05). No differences among dietary treatments were found for fat color values on a subjective basis. Pigs fed diet 5 had a more desirable objective fat color than pigs fed all white corn, and diets 1, 3, and 4 were not different (P > 0.05). Pigs fed diet 5 had greater levels of SFA and MUFA, and lower levels of unsaturated fatty acids and PUFA, in the subcutaneous fat than pigs fed all other diets. These results indicate that the energy sources evaluated in this study had little effect on eating quality of pork that was held for 25 to 27 d postslaughter.     

The effect of supplementing layer diets with shark cartilage or chitosan on egg components and yolk lipids

1. An experiment was designed to evaluate the effects of the addition of shark cartilage (SC) or chitosan (CH) to layer diets on egg component weights, yolk lipids and hen plasma lipids. 2. Hy-Line laying hens (80) were used during a 56 d feeding trial. Treatments were: basal diet (BD), BD + 20 g/kg SC, BD + 30 g/kg SC, BD + 20 g/kg CH and BD + 30 g/kg CH. Eggs were analysed on d 14, 28, 42 and 56. 3. Egg weight and egg component weights were not affected by these treatments throughout the experimental period. 4. After 14d of experimental feeding, cholesterol levels were higher in eggs from birds given BD + 20 g/kg CH and BD + 30 g/kg CH than in those from birds given BD. 5. Furthermore, eggs from hens given BD + 20 g/kg SC or BD + 20 g/kg CH were higher in palmitic and stearic acids and lower in oleic acid than those from birds fed on BD. After 56 d feeding, however, palmitic and stearic acid contents in eggs from hens given any of the supplemented diets were lower than in those from hens given BD, and oleic acid in eggs from hens given BD + 20 g/kg SC, BD + 30 g/kg SC and BD + 30 g/kg CH was higher than in those from birds fed on BD. 6. Plasma cholesterol and triacylglycerol levels were not significantly affected by dietary treatment. 7. Shark cartilage or chitosan at up to 30 g/kg in layer diets did not affect egg component weights (yolk, white and shell) and total lipid contents. During the period from 42 to 56d of experimental feeding, diets containing up to 30 g/kg chitosan reduced egg yolk contents of cholesterol, palmitic and stearic acids and increased the content of oleic acid.     

Effects of dietary supplementation with conjugated linoleic acid on fatty acid composition and lipid oxidation in chicken breast meat

We investigated the effects of dietary conjugated linoleic acid (CLA) on fatty acid composition and lipid oxidation in breast meat of broiler chickens. Broiler chickens (28-day-old females) were fed diets containing experimental oils at 20 g/kg diet for 28 days. The experimental oils consisted of either a 2:0, 1:1, or a 0:2 (wt : wt) ratio of safflower oil (high linoleic acid content) to a commercial CLA mixture. In this study, dietary CLA supplementation significantly increased the composition and content of CLA in chicken meat. The predominant CLA in meat from birds with supplemented diets was the cis -9, trans -11 isomer. The proportion of saturated fatty acid in meat significantly increased with increasing CLA supplementation, with a corresponding decrease in monounsaturated fatty acid. Dietary CLA also reduced thiobarbituric acid reactive substances (TBARS) values in raw meat during storage at 4°C for 5 days. These results provide evidence that CLA feeding is a practical strategy not only for adding nutritional benefits to chicken meat but also for improving meat quality including oxidative stability.     

Supranutritional selenium level affects fatty acid composition and oxidative stability of chicken breast muscle tissue

A total of 128 broilers were used to investigate the effect of selenium (Se) on fatty acid (FA) composition and oxidative stability of lipids in the breast muscle tissue. There were 4 replicates of 4 dietary treatments: T1 (basal diet with no added Se), T2 (T1 with 0.15 mg Se added per kg diet), T3 (T1 with 0.3 mg Se added per kg diet) and T4 (T1 with 3.0 mg Se added per kg diet). A yeast source was used for added Se. Breast muscle tissue was collected from two chickens per replicate pen for the determination of Se concentration by ICP-MS, FA profile by GC and lipid oxidation using thiobarbituric acid reactive substances method. Addition of supranutritional Se levels to chicken diets leads to the production of Se-enriched meat. Consumption of 100 g of breast meat from chickens fed diets supplemented with 0.15, 0.3 and 3 mg Se per kg of diet can provide 26, 41 and 220 μg of Se, respectively. Long-chain polyunsaturated fatty acids namely C20:3n-6, C20:4n-6, C20:5n-3, C22:5n-3 and C22:6n-3 increased linearly (p = 0.047, p < 0.001, p = 0.023, p = 0.003 and p = 0.002, respectively) as the Se inclusion levels in the diets increased. At slaughter, a linear decrease in lipid oxidation (p = 0.019) was observed with Se addition, possibly attributed to the antioxidant properties of Se. Addition of supranutritional Se to chicken diets, at levels well below those causing toxicity, leads to production of Se-enriched meat, protection of health-promoting long-chain FA like C20:5n-3 and C22:6n-3 and protection of meat quality from oxidation at day 1 after slaughter.     

Effects of a multi-enzyme complex on growth performance,nutrient utilization and bone mineralization of meat duck

Background:Previous studies with broiler have shown dietary supplementation with multi-enzyme complex containing non-starch polysaccharides(NSP) degrading enzymes and phytase is efficient in releasing phosphorus(P),calcium(Ca),energy and amino acids from corn-soybean meal diets or corn-sorghum diets,hence compensating considerable levels of nutrients in formulation.Notwithstanding,such potentials have not been well defined in duck nutrition.Giving China being the largest duck producing country,we conducted this study to establish adequate specifications of major nutrients along with multi-enzyme complex to meat duck from day-old to slaughter,focusing on performance,utilization of nutrients and bone mineralization.Five dietary treatments were:Positive control(PC,T1):the nutrients concentration of diet for 1 to 14 d of age were apparent metabolizable energy(AME) 2,800 kcal/kg,crude protein(CP)19.39%,Ca 0.85%,available phosphorus(avP) 0.42%;for 15 to 35 d of age these parameters were AME2,900 kcal/kg,CP 16.47%,Ca 0.76%,avP 0.38%;Negative control 1(NC1,T2),the AME and digestible amino acids(DAA)were reduced by 70 kcal/kg and 2.0%,avP and Ca by 1.0 g/kg from PC diet;Negative control 2(NC2T4),the downspec from PC diet was AME 100 kcal/kg,DAA 2.5%,avP 1.5 g/kg and Ca 1.2 g/kg;The enzyme complex was added at the same dosage(200 ml7 1,000 kg) on NCI(T3) and NC2(T5) diets.Results:Comparing with the ducks fed on T1,T3 and T5 diets,the birds fed on NC2 diet showed the lowest(P 0.05)body weight(d 14 and 35),feed intake(d 35),tibia ash,Ca and P contents(d 14 and 35),and the utilization of nutrients(P 0.05).The supplementation with the enzyme complex to the NC diets restored growth rate,utilization of nutrients and bone mineralization to the level of the PC diet,and increased AME by 60 kcal/kg and117 kcal/kg,respectively for the NCI and NC2 diets.Conclusion:These results suggest that down-spec AME by 100 kcal/kg,DAA by 2.5%,avP by 1.5 g/kg and Ca by1.2 g/kg caused detrimental effects on duck performance compared with those fed on the PC diet,and these performance losses can be compensated by the addition of the multiple-enzyme complex.     

Effect of dietary protein source and lysine:DE ratio on growth performance, meat quality, and body composition of growing-finishing pigs.

The effects of four protein sources (soybean meal, sunflower meal, pea, and fish meal as the main protein source) and three apparent ileally digestible Lys:DE ratios (0.50, 0.43, 0.36 and 0.42, 0.36, 0.30 g Lys/MJ DE for 30 to 60 kg BW and 60 to 105 kg BW, respectively) in pig diets on growing-finishing performance, and carcass and meat quality traits were investigated. Eight individually housed animals per treatment received the diets from 30 to 105 kg BW at a level of 3.0 times maintenance requirements of energy. The ileal digestibility of protein sources was determined in a previous digestibility experiment. Protein sources showed no differences in growth performance from 30 to 105 kg BW. From 30 to 60 kg BW soybean treatment had lowest performance. The protein sources had no effect on lean meat percentage, liver weight, or meat quality (intramuscular fat content, pH at 45 min and 24 h after slaughter, drip loss, and meat color measured 24 h and 4 d after slaughter). The experimental diets formulated on the basis of similar apparent ileal digestible lysine content resulted in similar body composition regardless of the protein source used (P > 0.05). Reducing the Lys:DE ratio from 0.50/0.43 to 0.36/0.30 (by about 28%) reduced BW gain by 119 g/d from 30 to 60 kg and by 151 g/d from 60 to 105 kg BW. The gain:feed ratio increased by 82 g/kg in the first phase and by 47 g/kg in the second phase for the highest Lys:DE treatment compared with the lowest. Reducing Lys:DE ratio did not modify meat quality traits. A high Lys:DE ratio was associated with a high lean meat percentage. Differences between the medium- and low-Lys:DE groups were not significant. Lowering the Lys:DE ratio increased (P < 0.05) crude fat and fatty tissue content and decreased (P < 0.05) protein and muscle content in the body. Ash content and bone volume were not affected by Lys:DE ratio (P > 0.05). The chemical composition of the carcass can be predicted with moderate accuracy (R2 = 0.39 to 0.58) using volumetric composition data of previously frozen carcasses. In conclusion, similar growth performance, carcass and meat quality, and body composition can be expected if diet formulation is based on the apparent ileally digestible amino acid contents of feedstuffs, independent of dietary protein sources. Diminishing Lys:DE ratios reduce growth performance but do not modify meat quality traits. The chemical composition of the carcass can be predicted with moderate accuracy using the volumetric composition of thawed carcasses.     

日粮中添加亚麻籽油对鸡蛋脂肪酸组成和风味的影响

试验旨在研究日粮中添加亚麻籽油对蛋鸡生产性能、蛋品质、蛋黄脂肪酸组成及鸡蛋风味的影响。选取40周龄海兰灰商品代蛋鸡288只,随机分为4组,每组8个重复,每个重复9只鸡。设计分别添加0、0.5%、1.0%和3.0%亚麻籽油的4种等能等氮日粮。预试期1周,正试期4周。结果显示：①日粮中添加0.5%、1.0%、3.0%亚麻籽油对产蛋鸡生产性能、蛋品质均无显著影响（P>0.05）;②亚麻籽油可显著提高蛋黄中α-亚麻酸（ALA）、二十碳五烯酸（EPA）、二十二碳六烯酸（DHA）及总n-3多不饱和脂肪酸（PUFA）含量,且其随亚麻籽油添加水平增加呈线性和二次变化（P<0.05）;③3.0%亚麻籽油组显著降低了蛋黄气味及滋味评分,同时显著增强了蛋黄鱼腥气味及滋味评分（P<0.05）,而蛋黄总体接受度显著降低（P<0.05）,且其均随亚麻籽油添加水平增加呈线性和二次变化（P<0.05）;④鸡蛋蛋黄总n-3 PUFA含量与鱼腥气味、滋味间具有显著相关性（P<0.05）,且鸡蛋蛋黄接受度随n-3 PUFA含量增加而降低（R²=0.801）。综上所述,日粮添加亚麻籽油可提高蛋黄总n-3 PUFA含量,但添加量过高时对鸡蛋风味产生不良影响导致总体接受度下降;蛋黄总n-3 PUFA含量不高于21.26 mg/g时,可接受度评分大于5分,鸡蛋感官品质在可接受范围内。     

Influence of exogenous application of n-3 fatty acids on meat quality, lipid composition, and oxidative stability in pigs.

The effect of dietary n-3 fatty acids on the fatty acid composition and lipid peroxidation of different tissues in pigs were studied. 20 castrated male pigs were included in this investigation, one half was fed daily a diet containing 1.3 g n-3 fatty acids/kg diet (control) and 10 pigs were fed a diet containing 14 g n-3 fatty acids/kg diet (n-3 diet) at the growing-finishing period. The intake of dietary n-3 fatty acids increased the concentration of these fatty acids in backfat, and the neutral and polar fractions of skeletal muscle and heart homogenates. The polar fraction showed an increased relative concentration of n-3 fatty acids in comparison to control, while the n-6 fatty acid content was reduced. In heart homogenates there was an enlargement of n-3 fatty acids both in polar lipids and in neutral lipids whilst n-6 fatty acids were decreased. Feeding n-3 fatty acid enriched diet had no influence on meat quality parameters drip loss, meat colour or pH value. The lipid peroxidation (measured as malondialdehyde equivalents) was in the order liver > heart > skeletal muscle with higher values in the n-3 group. However, by stimulation of oxidation by Fe2+/ascorbate for 3 hours the order of oxidative products in the n-3 group was muscle > liver > heart, whereas in the control group the order was liver > heart = muscle. Summarized, feeding a highly n-3 fatty acid enriched diet caused an incorporation of these fatty acids and increased the susceptibility to peroxidation in all investigated tissues.