F. Z. Liu

University of Arkansas, Fayetteville, Arkansas, United States

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Publications (20)9.83 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Effects of preslaughter immunological stress induced by lipopolysaccharide (LPS) on antioxidant performance and meat quality of broilers were investigated. Twenty-four broiler chickens (39 days old) with near-mean body weight (BW) were randomly divided into three following treatments: sham injection of saline (control), daily subcutaneous (s.c.) injection of LPS (3 mg/kg or 6 mg/kg of BW, respectively.) for three days. The results showed that average daily feed intake and daily gain of chickens were significantly decreased in the LPS treatment (P < 0.05). The F/G was significantly enhanced (P < 0.01). The LPS treatment had no significant influence on carcass performance (P > 0.05). The LPS treatment significantly decreased the pH at 24 h postmortem in breast muscle (P < 0.05) and significantly increased the water-holding capacity (WHC) of breast muscle (P < 0.01). It was the same as the change of yellowness (b*) at day 3 postmortem and lightness (L*) at day 6 postmortem in breast muscle (P < 0.05), but had no significant influence on shear force of breast muscle (P > 0.05). The pH at 45 min or 24 h postmortem of thigh muscle was significantly dropped in the LPS treatment (P < 0.01), however, the WHC and shear force of thigh muscle were not significantly different (P > 0.05). The yellowness (b*) significantly increased at day 3 postmortem of thigh muscle (P < 0.05). The plasma, breast muscle and thigh muscle MDA were significantly enhanced in the LPS treatment (P < 0.05). The total antioxidant capacity (T-AOC) level was significantly suppressed (P < 0.05); however, the plasma activity of glutathione peroxidase (GSH-Px) was slightly decreased (P > 0.05). The results of present study suggested that LPS-induced preslaughter immunological stress could increase body oxidative damage and decrease oxidation resistance, resulting in a decrease in growth performance and meat quality of broilers; also these adverse effects could be rested with the stress intensity.
    Journal of Applied Animal Research 05/2015; DOI:10.1080/09712119.2015.1031771 · 0.48 Impact Factor
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    ABSTRACT: Distillers dried grains with solubles (DDGS) from corn contain relatively large amounts of polyunsaturated fatty acids and some yeast components, which may increase oxidative stress and alter immune function, respectively, when fed to broilers. Therefore, the study was undertaken to assess the effects of distillers dried grains with soluble (DDGS) on broilers under immunosuppressive challenge. One-day-old male broiler chickens (300) were assigned to 2 treatments with 6 replicates pretreatment. Birds were fed diets formulated to contain 0, 15% corn-based DDGS, respectively. The experimental diets were fed for 6 weeks in 2 phases. On day 21, serum IgA, IgG content and malondialdehyde (MDA), glutathione peroxidase (GSH-Px), total superoxide dismutase (T-SOD), and total antioxidant activity (T-AOC) capacity were analyzed. Chickens were then randomly allotted to 1 of 4 treatment groups: negative control (NC) corn-soybean meal diet without dexamethasone (DEX) challenge, positive control (PC) corn-soybean meal diet with (DEX) challenge, 15% DDGS without DEX challenge (D), 15% DDGS with DEX (D+DEX). Based on these results, dietary DDGS did not influence ADG, ADFI and F:G of 21 d, 28 d and 42 d chicks (P > 0.05), however, DEX affected ADG and F:G of 28 d chicks remarkably (P < 0.05). Relative weights of liver, abdominal fat, spleen, thymus, and bursa were influenced by DEX challenge on d 28 (P < 0.05). DDGS reduced serum T-AOC, T-SOD, whereas increased IgA, IgG and MDA of 21-day-old broilers significantly (P < 0.05). Dietary DDGS also reduced liver T-SOD of 21-day-old broilers significantly (P < 0.05). Based on real-time PCR, 28 d chicks fed DDGS had a greater relative abundance of mRNA encoding IL-4 and IL-6 (P < 0.05), whereas DEX decreased the expression of GPX, IL-6, IL-10 (P < 0.05). Thus, 15% dietary DDGS inclusion has the beneficial effects on immune functions for broilers to some degree.
    The Journal of Applied Poultry Research 03/2015; 24(1). DOI:10.3382/japr/pfv002 · 0.59 Impact Factor
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    ABSTRACT: This study was undertaken to assess dietary crude protein (CP) concentration for optimum growth performance and carcass characteristics of Lueyang black-boned chicken. In total, six hundred 42-day-old Lueyang black-boned chicks were randomly assigned to five treatments, each with six replicate pens with ten males and ten females. The birds fed experimental diets with different levels of protein concentration of 120, 140, 160, 180 and 200 g kg-1 from seven to twelve weeks of age respectively. On day of 84, weight gain, feed intake, and feed:gain ratio were measured, and two chickens (one male and one female) close to the average weight of all birds in each treatment were selected from each pen and sacrificed to evaluate carcass traits and selected serum biochemical indexes. Dietary CP concentration did not have any significant influence on feed intake (p>0.05). The birds fed the diet with 180 or 160 g kg-1 CP concentration exhibited greater (p<0.05) growth rate, better feed conversion ratio, relative breast weight and albumin concentration in serum than that of those fed other dietary CP concentrations. According to the results of regression analysis, the CP requirements of Lueyang black-boned chicken from seven to twelve weeks of age for optimal weight gain and feed:gain ratio were 174 and 170 g kg-1, respectively.
    Revista Brasileira de Ciência Avícola 01/2015; 17(1):103-108. DOI:10.1590/1516-635x1701103-108 · 0.32 Impact Factor
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    ABSTRACT: To investigate the effect of humidity and ammonia on the antioxidative capacities and meat qualities of broilers, 192 broilers were divided into 2 groups: high (H, 70 ppm) and low (L, 30 ppm) ammonia concentration. These groups were divided into 30% (Treatment humidity, T) and 60% (Control humidity, C) humidity, giving 4 treatments: C+L, C+H, T+L, and T+H. Blood and muscle antioxidative capacities and meat quality were measured. In the H group, body weight (BW), average daily feed intake (ADFI), average daily weight gain (ADG), blood and muscle antioxidative capacities, and postmortem pectoral muscle a* of broilers were significantly decreased (P < 0.05), and pectoral muscle thiobarbituric acid reactive substance (TBARS) contents and drip losses, postmortem pectoral muscle b* (P < 0.05) and L* (P = 0.054), and pectoral muscle shear forces (P = 0.075) increased. In the T condition, BW, ADFI, pectoral muscle superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, and pectoral muscle L* decreased (P = 0.053), and pectoral muscle shear forces and TBARS contents increased (P < 0.05). In the T+H group, BW, ADFI, ADG, blood antioxidative capacities, pectoral muscle SOD and GSH-Px activities, and postmortem pectoral muscle a* were significantly lower than those of the C+L group, but postmortem pectoral muscle TBARS contents and pectoral muscle drip losses and shear forces significantly increased (P < 0.05). These results revealed that T+H could significantly reduce growth performance, antioxidative capacities, and meat quality of broilers; T intensified these negative effects.
    Genetics and molecular research: GMR 01/2014; 13(2):3117-3127. DOI:10.4238/2014.April.17.8 · 0.85 Impact Factor
  • Journal of Animal and Veterinary Advances 12/2012; 11(19):3652-3657. DOI:10.3923/javaa.2012.3652.3657 · 0.37 Impact Factor
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    ABSTRACT: This experiment was conducted to evaluate the effects of distillers dried grains with solubles (DDGS) on the meat quality and antioxidant status and capacity of broiler chickens. One-day-old male broiler chickens (720) were assigned to 6 treatments, with 4 replicates per treatment. Birds were fed diets formulated to contain 0, 5, 10, 15, 20, and 25% corn-based DDGS, respectively, for a period of 6 wk. The addition of DDGS influenced the general meat quality by affecting the b* (yellowness) values, cooking loss, and shear force (P < 0.01). Moreover, the fatty acid profiles of the breast and thigh were affected by DDGS levels. In particular, no significant difference was found in saturated, monounsaturated, and polyunsaturated fatty acids (P > 0.05), but feeding DDGS significantly increased the ratio of polyunsaturated to saturated fatty acids (P < 0.01). In breast meat and liver tissue, total superoxide dismutase activity decreased significantly between birds fed the control diet and the DDGS diets (P < 0.05). In the liver, glutathione peroxidase activity was similar to that of the control group in the diet with 15% added DDGS (P < 0.01). The malondialdehyde production of breast muscle was not affected (P > 0.05) by dietary DDGS concentrations; however, liver malondialdehyde production was influenced significantly (P < 0.01) by dietary DDGS levels. Overall, including DDGS at concentrations up to 15% in the broiler diet is feasible and can result in ideal meat quality.
    The Journal of Applied Poultry Research 09/2012; 21(3):603-611. DOI:10.3382/japr.2011-00503 · 0.59 Impact Factor
  • International Journal of Poultry Science 10/2011; 10(10):786-795. DOI:10.3923/ijps.2011.786.795
  • International Journal of Poultry Science 10/2011; 10(10):796-803. DOI:10.3923/ijps.2011.796.803
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    ABSTRACT: The experiment was conducted to investigate the effects of dihydropyridine supplementation on the laying performance and lipid metabolism of broiler breeder hens. A total of 720 forty-five-week old broiler breeder hens were randomly divided into four experimental groups, each group consisting of six replicates of 30 birds. For 10 weeks the birds were fed a maize-soybean meal diet containing 0, 100, 200, 300 mg dihydropyridine/kg, in the respective treatment groups. The daily egg weight and daily feed intake were not affected by dihydropyridine supplementation, but the laying rate and feed efficiency were significantly increased. The percentage of abdominal fat and percentage of liver fat were significantly decreased by dietary dihydropyridine. A level of 100 mg dihydropyridine/kg had no effect on hormone-sensitive triglyceride lipase (HSL) activity in the liver or abdominal fat, though higher levels of dietary dihydropyridine (200 mg/kg or 300 mg/kg) increased HSL activity in the liver and abdominal fat. The concentration of cyclic adenosine monophosphate (cAMP) and superoxide dismutase activity were significantly increased by dihydropyridine, but the malondialdehyde content decreased. The apolipoprotein B concentration was increased at levels of 100 and 200 mg dihydropyridine/kg, but the 300 mg level had no effect on apolipoprotein B, compared with the control group. The triiodothyronine concentration was significantly increased by dietary dihydropyridine. It is concluded that supplementing dihydropyridine in the diet has a beneficial effect on the laying performance and regulates the fat metabolism of broiler breeder hens. The results suggest that the supplementation of 200 mg dihydropyridine/kg diet is the optimal dose for broiler breeder hens.
    South African Journal Of Animal Science 12/2010; 41(4):331-336. DOI:10.4314/sajas.v41i4.2 · 0.35 Impact Factor
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    ABSTRACT: Glycerin, known as glycerol or glycerine, is the principal co-product of biodiesel production, produced through a NaOH- or KOH-catalyzed transesterification of the triacylglycerols in oils or fats with an alcohol. Glycerin is known to be a valuable ingredient for producing food, soaps, cosmetics and pharmaceuticals. Currently, with plenty of glycerin available to the world market, more uses are expected to develop, especially as a potential energy source for poultry diets, with approximately 4,100 kcal/kg of gross energy. Moreover, glycerin also plays a critical role in body cellular metabolism. Results from different laboratories on the use of glycerin as feed energy source for poultry are discussed in this article. Positive responses are obtained with glycerol content up to 10% in poultry diets. The AMEn also has been measured in several experiments. However, more indices such as carcass performance and blood parameters need to be determined in further studies.
    International Journal of Poultry Science 01/2010; DOI:10.3923/ijps.2010.1.4
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    ABSTRACT: Two trials of similar experimental design were conducted to assess the effects of various dietary enzymes on energy digestibility of diets high in distillers dried grains with solubles (DDGS) for broilers. A 2 x 4 factorial arrangement of treatments was used in which a corn-soybean meal control diet and a diet with 30% DDGS were supplemented with 2 different commercial enzyme products. In addition to the unsupplemented control, each enzyme was fed at the level suggested by the manufacturer, twice the recommended level, and 4 times the recommended level. Allzyme SSF (Alltech, Nicholasville, KY) was used in the first experiment, and Rovabio Excel (Adisseo, Alpharetta, GA) was used in the second experiment. Male commercial strain chicks that were 15 (trial 1) or 20 (trial 2) d old were randomly assigned to the experimental diets, with each treatment replicated 3 times. Celite (Celite Corp., Santa Barbara, CA) was used as an indigestible marker. After a 5-d period of acclimation to the diets, excreta samples were collected. The energy contents of the diet and excreta were determined and digestibility of dietary energy was calculated. In both trials, there was a significant (P < 0.05) difference in gross energy digestibility between the corn-soybean meal control diets and diets with 30% DDGS. However, no significant improvement in gross energy digestibility was obtained by adding any level of the 2 enzymes. Moreover, no significant interactions were found between the basal diets and various enzyme levels. Therefore, addition of the enzymes used in these studies had no apparent beneficial effect on energy digestibility of corn-soybean meal diets or diets with a high level of DDGS.
    The Journal of Applied Poultry Research 11/2009; 18(4):734-740. DOI:10.3382/japr.2009-00046 · 0.59 Impact Factor
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    ABSTRACT: The development of the fuel ethanol industry has resulted in large quantities of distillers dried grains with solubles (DDGS). This can partially replace corn and soybean meal in broiler diets, but the amino acids in DDGS are not balanced. Canola meal (CM) is a good protein source with a high amino acid content, so the combined use of DDGS and CM may improve the amino acid balance. A study was conducted to evaluate the use of DDGS in combination with CM in broiler diets. In a 6 × 6 factorial arrangement, 1,080 one-day-old male broilers were randomly assigned to diets with 0, 5, 10, 15, 20, and 25% DDGS of known composition; within each level of DDGS, diets contained 0, 5, 10, 15, 20, or 25% CM from 0 to 18 d of age. Each treatment was replicated 6 times. Diets were formulated to meet digestible amino acid requirements and were fed as a 3.17-mm pellet. Body weight and feed consumption were measured at 18 d of age. In addition, feed bulk density and percentage of fines were evaluated. The DDGS and CM levels as well as their interaction significantly affected feed intake and BW (P < 0.05). Moreover, feed intake and BW declined dramatically with the increasing inclusion of CM. However, no significant difference was noted in FCR due to dietary DDGS and canola levels. Percentage of fines and diet bulk density were influenced significantly by dietary DDGS and CM levels as well as by their interaction. The percentage of fines increased with increasing combinations of DDGS and CM. However, the effect of dietary DDGS and canola concentrations on feed bulk density did not show a clear trend. By regression analysis, percentage of fines had a significant impact on feed intake and BW gain but failed to show any clear-cut relationship between bulk density and performance factors. Therefore, when DDGS and CM are used in combination, the total level of the 2 ingredients in the formulation should be considered.
    The Journal of Applied Poultry Research 11/2009; 18(4):725-733. DOI:10.3382/japr.2009-00050 · 0.59 Impact Factor
  • Z Y Niu, F Z Liu, Q L Yan, W C Li
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    ABSTRACT: This experiment was undertaken to evaluate the effect of dietary vitamin E on growth performance and immune response of broilers under heat stress (HS). Birds raised in either a thermoneutral (23.9 degrees C constant) or HS (23.9 to 38 degrees C cycling) environment were fed a corn-soybean meal basal diet supplemented with vitamin E at 0, 100, or 200 mg/kg, respectively. Two hundred forty 1-d-old male broiler chicks were randomly assigned to 6 groups; each group had 4 replicates of 10 birds. Humoral immunity was assessed by i.v. injection of 7% SRBC followed by evaluation of serum for antibody titers in primary and secondary responses. Cell-mediated immunity was assessed by using a Sephadex stimulation method to recruit abdominal exudate cells (AEC) to evaluate macrophage phagocytic ability. Body weight and feed intake were not significantly influenced by dietary vitamin E (P>0.05), whereas feed conversion was significantly affected by vitamin E at 100 mg/kg (P<0.05). Heat stress significantly reduced BW, feed intake, and feed conversion (P<0.05). Numbers of AEC, percentage of macrophages in AEC, phagocytic macrophages, and internalized opsonized and unopsonized SRBC were increased by dietary vitamin E (P<0.05). Both primary and secondary antibody responses were significantly increased by dietary vitamin E when birds were exposed to HS (P<0.05). Lymphoid organ weights, antibody responses, incidence of macrophages in AEC, and phagocytic ability of macrophages were all significantly reduced under HS. These results indicated that HS severely reduced growth performance and immune response of broilers, whereas the immune response of broilers could be improved by dietary vitamin E supplementation under HS.
    Poultry Science 10/2009; 88(10):2101-7. DOI:10.3382/ps.2009-00220 · 1.67 Impact Factor
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    ABSTRACT: This experiment was undertaken to evaluate the effect of dietary vitamin A on the performance and immune competence of broilers under heat stress (HS). A total of 180 birds, at 22 days of age, were randomly assigned to be reared either at 24°C (thermoneutral, TN, 24°C, constant) or 24°C to 38°C (heat stress, HS, cycling) until the age of 42 days. Birds were then supplemented with vitamin A at 750, 1500, 15 000 IU/kg. Each of the 2 × 3 factorially arranged treatments were replicated in six cages, each containing five birds. Humoral immunity was assessed by intravenous injection of 7% sheep red blood cells (SRBC) followed by evaluation of serum for antibody titers in primary and secondary responses. Cell-mediated immunity was assessed by using a Sephadax stimulation method to recruit abdominal exudate cells (AEC) to evaluate macrophage phagocytic ability. Body weight (BW) and feed conversion were significantly affected by dietary vitamin A (P < 0.05). HS significantly reduced BW, feed intake and feed conversion (P < 0.05). Numbers of AEC, percentage of macrophages in AEC, phagocytic macrophages, internalized opsonized and unopsonized SRBC were increased by dietary vitamin A (P < 0.05). Both primary and secondary antibody responses were characterized by increasing titers of antibody to SRBC by dietary vitamin A when birds were exposed to HS (P < 0.05). Lymphoid organ weights, antibody responses, incidence of macrophages in AEC and phagocytic ability of macrophages were all significantly reduced under HS. These results indicated that HS severely reduced performance and immunocompetence of broilers, whereas the immune response of broilers improved by dietary vitamin A supplementation under HS.
    animal 10/2009; 3(10):1442-8. DOI:10.1017/S1751731109990358 · 1.78 Impact Factor
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    ABSTRACT: An experiment was conducted to evaluate the use of distillers dried grains with solubles (DDGS) combined with glycerin in broiler diets. In a 3x2 factorial arrangement, 600 one-day-old commercial strain Cobb 500 broilers were randomly assigned to experimental diets with 0, 15 and 30% DDGS of known composition; within each level of DDGS the diets contained 0 or 5% glycerin, respectively, from 0-42 days of age. Diets were formulated to meet digestible amino acid requirements and were fed in pelleted form. Each dietary treatment was replicated 4 times. Body weight gain and feed consumption were measured and carcass characteristics were evaluated at 42 days of age. Inclusion of 30% DDGS had no adverse effect on body weight of chicks; however birds fed diets with 30% DDGS had greater feed intake and poorer feed conversion than birds fed the control diet at most age periods. This was highly correlated to the reduced pellet quality of diets containing the high levels of DDGS. Birds fed diets with 30% DDGS also had significantly reduced dressing percentage compared to birds fed the control diet with no DDGS. However, there was no adverse effect on breast meat yield related to the higher levels of DDGS inclusion. Addition of 5% glycerin from biodiesel production to the diets had no significant effect on body weight, feed intake, or feed conversion. There was no significant effect of the addition of glycerin on dressing percentage or yield of various carcass parts. With one minor exception, there was no significant interaction between addition of glycerin and level of DDGS in the diet, even though pellet quality declined when glycerin was added to the diets. Overall, the results of this study demonstrates that 15% DDGS of known nutritional quality can be utilized in diets for growing broilers with no adverse effects provided diets are formulated on a digestible amino acid basis and meet the nutritional requirements of the broiler. Higher levels may be tolerated but there may be a loss in feed conversion unless pellet quality can be improved. A loss in dressing percentage at higher levels of DDGS has been consistently noted in this and previous studies. Incorporation of 5% glycerin from biodiesel production as a source of energy appears satisfactory.
    International Journal of Poultry Science 07/2008; 7(7). DOI:10.3923/ijps.2008.646.654
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    ABSTRACT: The study was undertaken to assess dietary CP and ME concentrations for optimum growth performance and carcass characteristics of goslings. In a 5 x 3 factorial arrangement, 360 one-day-old commercial generation Huoyan goslings were randomly assigned to experimental diets with 10.87, 11.37, 11.87, 12.37, and 12.87 MJ of ME/kg of diet; each contained 15.0, 17.5, and 20.0% CP, respectively, from 0 to 4 wk of age (WOA). Each dietary treatment was replicated 6 times. Body weight and feed consumption were measured, and carcass characteristics were evaluated at 4 WOA. The result showed that birds on a diet with 11.87, 12.37, and 12.87 MJ of ME/kg at 0 to 4 WOA exhibited greater BW gain than those on a diet with 10.87 and 11.37 MJ of ME/kg (P < 0.01), though BW gain was not different among 11.87, 12.37, and 12.87 MJ of ME/kg of diet. Mean BW gain of birds fed 17.5 and 20.0% CP diets was not different (P > 0.05), but they were higher than those on 15.0% dietary CP concentration (P < 0.001). Feed intake was not influenced by dietary ME levels (P > 0.05). Feed intake of birds fed 17.5 and 20.0% CP diets was higher than those of birds on 15.0% CP diets (P < 0.01). Feed conversion ratios of birds fed on 11.87, 12.37, and 12.87 MJ of ME/kg of diet were better than those fed on 10.87 and 11.37 MJ of ME/kg (P < 0.001). Feed conversion ratios of birds fed on 17.5 and 20.0% CP diets were better than those fed on 15.0% CP diets. Moreover, there were no significant interactions between CP and ME on growth performance. There was a direct relationship between dietary ME levels and eviscerated carcass percentage, abdominal fat percentage, and liver relative weight (P < 0.01). Breast and leg meat percentage were influenced by dietary CP concentrations significantly (P < 0.001). Thus, diets with 11.87 MJ of ME/kg and 17.5 to 20.0% CP were used more efficiently from 0 to 4 WOA by Huoyan goslings.
    Poultry Science 05/2007; 86(4):661-4. DOI:10.1093/ps/86.4.661 · 1.67 Impact Factor
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    ABSTRACT: Three experiments were conducted to determine the optimal feed input and excreta collection time by a bioassay of dietary true metabolisable energy ( TME) for ducks. In experiment 1 and experiment 2, the time for the unabsorbed feed passage through the alimentary canal was determined by measuring the DM and energy of excreta and feed residues in the alimentary canal at different periods. In experiment 3, the feed input of force-feeding was studied and a total of 70 mature Pekin drakes were allotted to 7 groups, each group containing 10 birds. After fasting for 36 h, one group served as a negative control to measure metabolic faecal energy plus endogenous urinary energy and the drakes of the other 6 groups were force-fed pelleted feed 30 g, 50 g, 70 g, 90 g, 110 g, and 150 g per bird, respectively. Energy excretion of the periods of 16-28 h after force-feeding was significantly higher than that of the periods after 32 h, and the total energy excretion of the periods after 32 h (P < 0.05). When the feed input increased from 30 g to 70 g, the value of TME was constant ( P > 0.05). Metabo- lisable energy decreased significantly with an increase in feed input when the feed input was higher than 70 g (P < 0.05). It was concluded that the optimal time of feed withdrawal before tube-feeding and during excreta collection would be 32-36 h. The optimal feed input was 50 g to 70 g per drake.
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    Han X.F, Niu Z.Y, Liu F.Z, Yang C.S
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    ABSTRACT: A series of sequential experiments were carried out to determine optimum diluents, cryoprotectants, equilibration time, and thawing temperature for frozen duck semen in order to set up the commercial semen cryopreservating techniques which could be applied to the conservation of genetic resources, breeding, and commercial production in domestic ducks. In experiment 1, the seven semen extenders were studied to determine efficacy of the diluent on cryopreservation of duck Semen. The result showed that the diluent which contains 0.14% potassium citrate, 1.40% sodium glutamate, 0.98% disodium hydrogen phosphate, 0.21% sodium dihydrogen phosphate, 0.7% glucose, and 0.7% inositol was better than other six semen diluents. In experiment 2, the effects of various concentrations of cryoprotectants including glycerol, dimethyl sulphoxide (DMSO), dimethyl acetamide (DMA), and dimethyl formamide (DMF) on cryopreservation of bird semen were evaluated. The results showed that the cryoprotectant containing 10% DMSO was better than others. The experiment 3 was conducted to determine the effect of equilibration time and thawing temperature on cryopreservation of bird semen. The optimum equilibration time was 15 min and the optimum thawing temperature was 40°C
    International Journal of Poultry Science 04/2005; DOI:10.3923/ijps.2005.197.201
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    ABSTRACT: This experiment was conducted to evaluate the accuracy of a bioassay method for metabolizable energy for domestic duck, which was previously developed by our research group. 110 adult Peking drakes with similar weight were randomly allotted to 2 groups in each of 55 birds, one was treatment group and another was control group. Prior to trial, all birds were fasted for 12h, but water were provided ad libitum . And 5 birds from each group were web-bled from their venous in wings. At the same time, each bird of the tow groups was force-fed by pelleted feed 50g, then they were fasted but water was provided ad libitum . 4h later, drakes of the trial group were intake glucose saturated solution once every 6h for 15 minutes. At 2h, 12h, 24h, 36h, 48h after force-feeding, ten birds from each group were web-bled and discarded, respectively. Contents of glucose, uric acid, total protein, triglyceride, insulin, triiodothyronine, corticosteroid in plasma were measured. The results indicated that contents of glucose, uric acid and total protein in plasma didn`t fluctuate during the starvation of 48h. However, the content of triiodothyronine in plasma tended to decline, but it showed nonsignificant (p>0.05). Therefore, those drakes weren`t in abnormal conditions. Feeding glucose saturated solution to fasted drakes could alleviate the decrease of triiodothyronine in plasma. Fast resulted in the decease of insulin content in plasma. The plasma insulin content of fasted drakes fed glucose saturated solution is steady. Force feeding and fast didn`t cause the change of the corticosteroid content in plasma, which indicated that forementioned treatments didn`t make ducks under stress.
    International Journal of Poultry Science 04/2005; DOI:10.3923/ijps.2005.202.205
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    Z. Y. Niu, F. Z. Liu, Y. N. Min
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    ABSTRACT: An experiment was conducted to investigate the effects of dihydropyridine supplementation on growth performance and lipid metabolism of broilers. A total of 480 one-day-old female Arbor Acres broiler chicks were randomly divided into four groups, each group had six replications of 20 birds. Each group was fed a maize-soybean meal diet supplemented with 0, 100, 200, 300 mg/kg dihydropyridine, respectively, for six weeks. At 42 days of age, body weight and feed intake were not affected by dihydropyridine, while feed efficiency was significantly increased by 8.4%, 15.0% and 12.0%, respectively ( P < 0.05). The percentage of abdominal fat and the percentage of liver fat were reduced by 24.5%, 25.9%, 23.3%, and 23.6%, 26.7%, 26.0%, respectively (P < 0.05). The higher level of dietary dihydropyridine (200 or 300 mg/kg) increased the hormone- sensitive triglyceride lipase activity in liver and abdominal fat ( P < 0.05). The lipoprotein lipase activity in abdominal fat was significantly decreased by dihydropyridine ( P < 0.05). The activity of glucose-6-phosphate dehydrogenase and malic dehydrogenase in liver was significantly reduced, whereas the isocitrate dehydro - genase activity in liver was not affected by dietary dihydropyridine. The content of cAMP was significantly increased by dihydropyridine, but malondialdehyde content was decreased ( P < 0.05). Dihydropyridine at doses of 100 and 200 mg/kg increased apolipoprotein B ( P < 0.05), but 300 mg/kg dihydropyridine had no effect on apolipoprotein B compared with the control group. Triiodothyronine was significantly increased by dietary dihydropyridine ( P < 0.05). There were no differences in apolipoprotein A, cholesterol, trigly- cerides, high density lipoprotein-cholesterol, very low density lipoprotein-cholesterol, thyroxine and insulin among dietary treatments. It is concluded that supplementing dihydropyridine has a beneficial effect on feed efficiency and lipid metabolism of broilers, and that 200 mg/kg dihydropyridine supplementation is the optimum dose.