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ABSTRACT: Experimental objectives were to determine the effects of supplemental saturated fatty acids on production, body temperature indices, and some aspects of metabolism in mid-lactation dairy cows experiencing heat stress. Forty-eight heat-stressed Holstein cows were allocated into 3 groups (n=16/group) according to a completely randomized block design. Three treatment diets consisted of supplemental saturated fatty acids (SFA) at 0 (SFA0), 1.5 (SFA1.5), or 3.0% (SFA3) of dry matter (DM) for 10 wk. Diets were isonitrogenous (crude protein=16.8%) and contained 1.42, 1.46, and 1.49 Mcal of net energy for lactation/kg of DM for the SFA0, SFA1.5 and SFA3 diets, respectively. The average temperature-humidity index at 0700, 1400 and 2200 h was 72.2, 84.3, and 76.6, respectively. Rectal temperatures at 1400 h were decreased with fat supplementation. Treatment did not affect dry matter intake (20.1+/-0.02 kg/d), body condition score (2.72+/-0.04), body weight (627+/-16.1 kg), or calculated energy balance (1.32+/-0.83 Mcal/d). Saturated fatty acid supplementation increased milk yield, milk fat content, and total milk solids. Increasing fat supplementation decreased plasma nonesterified fatty acids (8%) but had no effect on other energetic metabolites or hormones. In summary, supplemental SFA improved milk yield and milk fat content and yield and reduced peak rectal temperatures in mid-lactation heat-stressed dairy cows. This demonstrates the remarkable amount of metabolic heat that is "saved" by energetically replacing fermentable carbohydrates with supplemental SFA.
Journal of Dairy Science 09/2010; 93(9):4121-7. · 2.56 Impact Factor
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ABSTRACT: The objective of this study was to investigate the effect of dietary phytate and phytase on the metabolic parameters of lipid, protein, enzyme, electrolyte in the blood or intestinal mucosa of broiler chickens. Diets containing phytate phosphorus (0.22% or 0.44%) with phytase supplementation (0, 500 or 1000 U/kg) were administrated to 504 Cobb chicks for 4 weeks. Results showed that the serum concentrations of total cholesterol (T-CHO), albumin, albumin/globulin, total superoxide dismutase (T-SOD), total antioxidant capacity (T-AOC) and glutamic pyruvic transaminase (GPT) were decreased by 9-41% in high phytate diets (p < 0.05) and the concentrations of blood P, K, Fe, Cu, Zn and Mg were decreased by 4-14% for birds fed high phytate diets (p < 0.05), whereas inclusion of phytase compensated these adverse influences. In the duodenum, phytate decreased the level of T-AOC by 13% (p < 0.05), whereas phytase increased the levels of T-SOD, T-AOC and alkaline phosphatase (ALP) by 9-16% (p < 0.05). Also, in the jejunum, diets with high phytate showed lower activity of T-SOD, T-AOC and glutamic oxaloacetic transaminase (GOT) (p < 0.05), and phytase increased T-SOD, T-AOC and ALP (p < 0.05). However, phytase decreased transaminase activity in the low phytate basal diets (p < 0.05). This study suggests that dietary phytate can adversely interfere with the metabolisms of lipid and protein, as well as the antioxidation of blood and intestinal cells, while phytase supplementation may compensate these effects for broiler chickens.
J Anim Physiol a Anim Nutr 11/2009; 94(3):368-74. · 0.86 Impact Factor
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ABSTRACT: The effect of dietary phytate and phytase on carbohydrase activity and hexose transport was investigated in broiler chickens. Diets containing phytate P (2.2 or 4.4 g/kg) with different phytase dose rates (0, 500, or 1,000 phytase units/kg) were fed to 504 female Cobb chicks for 3 wk. Diets containing high phytate concentrations depressed (P < 0.05) BW and G:F, whereas phytase supplementation improved (P < 0.05) the performance of birds. In the duodenum, phytate decreased (P < 0.05) the activities of disaccharidases, Na(+)K(+)-ATPase, and glucose concentrations by 5 to 11%, but phytase enhanced (P < 0.05) the concentrations of amylase, sucrase, maltase, Na(+)K(+)-ATPase, and glucose by 5 to 30%. In the jejunum, phytate decreased (P < 0.05) the concentrations of amylase, sucrase, Na(+)K(+)-ATPase, and glucose by 10 to 22%, and phytase alleviated the negative effect of phytate on the above variables. Ingestion of diets containing phytate also decreased (P < 0.05) serum amylase activity and glucose concentration, and phytase enhanced (P < 0.05) serum concentrations of amylase, sucrase, maltase, Na(+)K(+)-ATPase, and glucose. There were also interactions (P < 0.05) between phytate and phytase on the concentrations of serum amylase, duodenal amylase, sucrase, and jejunal glucose. Enzymatic analysis at a molecular level showed that neither phytate nor phytase influenced the mRNA expression of sucrase-isomaltase in the small intestine. Also, the investigation into the sodium glucose cotransporter gene may challenge the mechanism by which phytate interferes with glucose utilization, as partly indicated by bird performance, and transmembrane transport because diets containing increased phytate upregulated (P < 0.05) the mRNA expression of the sodium glucose cotransporter gene in duodenum and did not influence it in the jejunum. These results indicate that phytate can impair endogenous carbohydrase activity and digestive competence, and phytase can ameliorate these effects for chickens.
Journal of Animal Science 08/2008; 86(12):3432-9. · 2.10 Impact Factor
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ABSTRACT: The effects of phytate and phytase on broiler performance and cellular and humoral immunity was assessed by using 504 Cobb 500 female broilers fed nutritionally marginal diets. At 1 d of age, the chicks were randomly allocated to 6 treatments in a 2 x 3 factorial arrangement including 2 levels of phytate P (0.22 or 0.44%) and 3 dose rates of an Escherichia coli-derived phytase [0, 500, or 1,000 phytase units (FTU)/kg of feed]. Both low- and high-phytate diets were corn and soy based with the same nutritional specifications (AME 2,900 kcal/kg, CP 21.00%, Ca 0.78%, and nonphytate P0.28%), differing only in the concentration of phytate P. The immune status of birds was measured at 14, 21, and 28 d of age. The results revealed that phytase improved feed intake, BW, and feed conversion ratio (P < 0.05), whereas high dietary phytate depressed bird performance (P < 0.05). There was no interaction between phytate and phytase on bird performance. Feeding phytase increased the percentages of erythrocyte rosette-forming cells and erythrocyte-antibody complement cells by 3.03 and 1.83% at d 21, and by 2.76 and 2.20% at d 28, respectively (P < 0.05). The percentages of CD4(+)CD8(+) T lymphocyte subsets were also increased by phytase (P < 0.05), without affecting the ratio of CD4(+) and CD8(+). The levels of intestinal secretory IgA were improved with phytase at d 14, 21, and 28 (P < 0.05). Antibodies against Newcastle disease virus vaccine were enhanced at d 21 and 28 in the high-phytate diets with phytase addition (P < 0.05). Increasing the phytase dose to 1,000 FTU/kg did not improve immune function further than 500 FTU/kg. The results suggest that application of phytase in nutritionally marginal diets could enhance lymphocyte numbers and the seral and mucosal antibodies of 1- to 28-d-old broilers, suggesting that both phytate and phytase may have a role in gastrointestinal health and immune competence.
Poultry Science 06/2008; 87(6):1105-11. · 1.73 Impact Factor
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ABSTRACT: The effects of phytases on the performance of layers and the ileal nutrient digestibility of corn-, soybean-, and by-product meal-based diets were assessed with 320 Hy-Line brown layers from 23 to 28 wk of age. Layers were grouped randomly into 5 treatments, with 8 replicates per treatment and 8 layers per replicate. The 5 diets consisted of a positive control diet with adequate Ca (3.30%), total P (0.50%), and nonphytate P (NPP; 0.28%), and a negative control diet with Ca reduced by 0.12%, total P reduced by 0.14%, NPP reduced by 0.13%, and 3 phytases (phytase A derived from Aspergillus niger, and phytases B and C derived from Escherichia coli) supplemented at 300 phytase units/kg of feed, respectively. Egg production and feed intake were recorded daily, and eggshell quality and ileal nutrient digestibility were measured at the end of a 6-wk feeding period. The results revealed that the reduction of Ca and P from the positive control diet significantly depressed feed intake, egg mass, eggshell hardness, and the digestibility of N, Ca, P, and amino acids (P < 0.05). Phytase supplementation in the negative control diet improved the digestibility of P and Ca by 11.08 and 9.81% (P < 0.05), respectively, whereas it improved the digestibility of amino acids by 2 to 8% (P < 0.05). However, the digestibility of most amino acids was not restored to the levels of the positive control diet by the application of phytases. Supplementing phytases in the negative control diet improved the rate of lay, egg mass, and egshell quality to the levels of birds fed the positive control diet. These results suggest that supplementing phytases can improve the digestibility not only of Ca and P, but also of amino acids in layers fed a corn-, soybean-, and by-product-based diet.
Poultry Science 11/2007; 86(11):2337-42. · 1.73 Impact Factor
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ABSTRACT: Sixty yak heifers were closely observed to determine their ages at sexual maturity and 15 heifers were used to analyze the plasma progesterone by radioimmunoassay before and at the attainment of puberty. Yak heifers began cyclic activity at a mean (+/-S.D.) age of 33 +/- 6.7 months, but with wild variation. Fifteen heifers used to determine plasma progesterone were divided into three age groups: group I (10-14 months, n = 5), group II (20-24 months, n = 5) and group III (30-36 months, n = 5). Group I yak heifers were found to have two progesterone profiles: inactive ovary (IO) profile and low progesterone short cycle (LPSC) profile; group II had three profiles: IO profile, LPSC profile and LPNC (low progesterone normal cycle) profile; group III had three profiles: LPSC profile, LPNC profile and a normal oestrous cycle profile. It would be concluded from the present study that one or two, or even more brief rise(s) in circulating progesterone presented in yak heifers. These rises, however, were not followed by a normal luteal phase except two yak heifers that came to heat. This characteristics found in yak was obviously different with that reported in other animals.
Animal Reproduction Science 02/2001; 65(1-2):67-73. · 1.75 Impact Factor
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ABSTRACT: The nodulation genes of Mesorhizobium sp. (Astragalus sinicus) strain 7653R were cloned by functional complementation of Sinorhizobium meliloti nod mutants. The common nod genes, nodD, nodA, and nodBC, were identified by heterologous hybridization and sequence analysis. The nodA gene was found to be separated from nodBC by approximately 22 kb and was divergently transcribed. The 2. 0-kb nodDBC region was amplified by PCR from 24 rhizobial strains nodulating A. sinicus, which represented different chromosomal genotypes and geographic origins. No polymorphism was found in the size of PCR products, suggesting that the separation of nodA from nodBC is a common feature of A. sinicus rhizobia. Sequence analysis of the PCR-amplified nodA gene indicated that seven strains representing different 16S and 23S ribosomal DNA genotypes had identical nodA sequences. These data indicate that, whereas microsymbionts of A. sinicus exhibit chromosomal diversity, their nodulation genes are conserved, supporting the hypothesis of horizontal transfer of nod genes among diverse recipient bacteria.
Applied and Environmental Microbiology 08/2000; 66(7):2988-95. · 3.83 Impact Factor
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ABSTRACT: This thesis introduces the measuring principle, device composition and main functions of an intelligent acoustic impedance middle ear analyzer. As well the results of clinical trial are analyzed in this paper. As an objective diagnostic method, aural acoustic impedance measuring device holds a very important position in diagnosing ear diseases and hearing obstacles.
Zhongguo yi liao qi xie za zhi = Chinese journal of medical instrumentation 04/2000; 24(3):140-2.
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ABSTRACT: Two hundred and four isolates of rhizobia were sampled from root nodules of Astragalus sinicus grown in rice fields of six southern provinces of China. Genotypic diversity was determined by Southern hybridization using nodDBC genes as a probe, restriction fragment length polymorphism (RFLP) analysis of PCR-amplified 16S-23S rDNA intergenic spacers (IGS), and plasmid profile. Our results show that rhizobia associated with A. sinicus were very diverse, and 10 genotypes were resolved within the previously identified dominant 16S rDNA type. Diversity levels varied greatly between different geographical locations. The same nod gene genotypes were harbored by distinct chromosomal types, suggesting that lateral plasmid transfer occurred during the evolution process.
Current Microbiology 01/2000; 39(6):358-0364. · 1.82 Impact Factor
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ABSTRACT: Rhizobium sp. strain S25 was isolated from the nodule on Tephrosia candida in Hainan Province, China. The strain showed high stress tolerance. The plasmid profile of strain S25, examined by the Eckhardt procedure, indicated that the strain harbors only one plasmid with an estimated size of 150 kb. The plasmid was shown to carry nod and nif genes by hybridization with probes of nodABC and nifHDK genes. Plasmid curing was carried out using the Bacillus subtilis sacB to generate derivatives of strain S25. In comparison with the parent strain S25, the cured derivative lost its ability to nodulate the host plant. Loss of the plasmid reduced significantly the strain's tolerance to acid, nitrous, and multiple antibiotics. The properties of the cured strain also indicated that the plasmid was involved in carbon and nitrogen metabolism. Reintroduction of the plasmid from S25 in the cured derivative restored its original biological phenotypes.
Plasmid 10/1998; 40(2):158-63. · 1.52 Impact Factor
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ABSTRACT: Rhizobiumsp. strain S25 was isolated from the nodule onTephrosia candidain Hainan Province, China. The strain showed high stress tolerance. The plasmid profile of strain S25, examined by the Eckhardt procedure, indicated that the strain harbors only one plasmid with an estimated size of 150 kb. The plasmid was shown to carrynodandnifgenes by hybridization with probes ofnodABCandnifHDKgenes. Plasmid curing was carried out using theBacillus subtilis sacBto generate derivatives of strain S25. In comparison with the parent strain S25, the cured derivative lost its ability to nodulate the host plant. Loss of the plasmid reduced significantly the strain's tolerance to acid, nitrous, and multiple antibiotics. The properties of the cured strain also indicated that the plasmid was involved in carbon and nitrogen metabolism. Reintroduction of the plasmid from S25 in the cured derivative restored its original biological phenotypes.
Plasmid.
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ABSTRACT: Experimental objectives were to determine the effects of supplemental saturated fatty acids on production, body temperature indices, and some aspects of metabolism in mid-lactation dairy cows experiencing heat stress. Forty-eight heat-stressed Holstein cows were allocated into 3 groups (n = 16/group) according to a completely randomized block design. Three treatment diets consisted of supplemental saturated fatty acids (SFA) at 0 (SFA0), 1.5 (SFA1.5), or 3.0% (SFA3) of dry matter (DM) for 10 wk. Diets were isonitrogenous (crude protein = 16.8%) and contained 1.42, 1.46, and 1.49 Mcal of net energy for lactation/kg of DM for the SFA0, SFA1.5 and SFA3 diets, respectively. The average temperature-humidity index at 0700, 1400 and 2200 h was 72.2, 84.3, and 76.6, respectively. Rectal temperatures at 1400 h were decreased with fat supplementation. Treatment did not affect dry matter intake (20.1 ± 0.02 kg/d), body condition score (2.72 ± 0.04), body weight (627 ± 16.1 kg), or calculated energy balance (1.32 ± 0.83 Mcal/d). Saturated fatty acid supplementation increased milk yield, milk fat content, and total milk solids. Increasing fat supplementation decreased plasma nonesterified fatty acids (8%) but had no effect on other energetic metabolites or hormones. In summary, supplemental SFA improved milk yield and milk fat content and yield and reduced peak rectal temperatures in mid-lactation heat-stressed dairy cows. This demonstrates the remarkable amount of metabolic heat that is “saved” by energetically replacing fermentable carbohydrates with supplemental SFA.
Journal of Dairy Science.
