Influence of level of dietary protein or energy on effects of ractopamine in finishing swine.     

A D Mitchell  M B Solomon  N C Steele 《Journal of animal science》1991,69(11):4487-4495

The effect of ractopamine, a beta-adrenergic agonist, on growth, nutrient utilization, and carcass composition was studied in pigs fed either 18% CP, 12% CP, or 18% CP restricted (RES = 67% of ad libitum) diets. The 18 and 12% CP diets provided 3.52 and 3.68 Mcal of DE/kg, respectively. All pigs were fed a low-protein (12% CP) diet during pretreatment growth from 15 to 60 kg. Ractopamine at 20 or 30 ppm (30 ppm for RES pigs) in the diet was fed from 60 kg live BW until slaughter at 105 kg (9 pigs/treatment). No ractopamine treatment effect (P greater than .05) was observed for either daily gain or gain/feed, although gain/feed was improved by 8% in both of the ad libitum groups. Ractopamine treatment resulted (P less than .01) in an overall reduction of carcass lipid by 8%, an increase of carcass protein by 5%, and a 21% improvement in the efficiency of protein utilization; the greatest changes occurred in the pigs fed the 12% CP diet (-17%, +11%, and +32%, respectively). The ad libitum daily feed intake was 15% less for pigs fed the 12% CP diet than for those fed the 18% CP diet (P less than .01), and there was a 10% reduction in intake of both diets with the addition of ractopamine (P less than .05). Both carcass lipid and protein deposition seemed to be closely related to energy intake (P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Genome‐wide analysis of genes associated with moderate and high DDT resistance in Drosophila melanogaster     

Xinghui Qiu  Weilin Sun  Cynthia M McDonnell  Hongmei Li‐Byarlay  Laura D Steele  Jing Wu  Jun Xie  William M Muir  Barry R Pittendrigh 《Pest management science》2013,69(8):930-937

  相似文献   

Wolf (Canis lupus) Predation Impacts on Livestock Production: Direct Effects,Indirect Effects,and Implications for Compensation Ratios     

Jordan R. Steele  Benjamin S. Rashford  Thomas K. Foulke  John A. Tanaka  David T. Taylor 《Strength and Conditioning Journal》2013,66(5):539-544

Growing wolf (Canis lupus L.) populations in the US Rocky Mountain Region have increased conflicts between livestock production and wolf conservation. Given that the costs of large carnivore conservation are disproportionately borne by local livestock producers, the United States uses compensation for wolf damage to reduce conflicts and mediate negative attitudes toward the predators. Current compensation programs, however, only consider the direct effects of wolf predation. Indirect effects, such as wolf effects on weaning weights, and conception rates, may also reduce profitability. By not including indirect wolf effects, compensation programs may systematically undercompensate ranchers. We use a stochastic budget model of a representative cow–calf ranch in northwest Wyoming to estimate the economic impact of both direct (death loss and injured calves) and indirect effects (decreased weaning weights, decreased conception rates, and increased cattle sickness) of wolf predation. Our results suggest that short-run (i.e., year-to-year) financial impacts of wolf indirect effects may be as large as or larger than the direct effects. Including indirect effects implies that the compensation ratio (i.e., number of calves compensated per confirmed depredation) necessary to fully offset the financial impacts of wolves would need to be two to three times larger than current 7:1 compensation ratio used in Wyoming.  相似文献   

Weak northern and strong tropical land carbon uptake from vertical profiles of atmospheric CO2     

Stephens BB  Gurney KR  Tans PP  Sweeney C  Peters W  Bruhwiler L  Ciais P  Ramonet M  Bousquet P  Nakazawa T  Aoki S  Machida T  Inoue G  Vinnichenko N  Lloyd J  Jordan A  Heimann M  Shibistova O  Langenfelds RL  Steele LP  Francey RJ  Denning AS 《Science (New York, N.Y.)》2007,316(5832):1732-1735

Measurements of midday vertical atmospheric CO2 distributions reveal annual-mean vertical CO2 gradients that are inconsistent with atmospheric models that estimate a large transfer of terrestrial carbon from tropical to northern latitudes. The three models that most closely reproduce the observed annual-mean vertical CO2 gradients estimate weaker northern uptake of -1.5 petagrams of carbon per year (Pg C year(-1)) and weaker tropical emission of +0.1 Pg C year(-1) compared with previous consensus estimates of -2.4 and +1.8 Pg C year(-1), respectively. This suggests that northern terrestrial uptake of industrial CO2 emissions plays a smaller role than previously thought and that, after subtracting land-use emissions, tropical ecosystems may currently be strong sinks for CO2.  相似文献   

Ruminant Nutrition Symposium: Molecular adaptation of ruminal epithelia to highly fermentable diets     

Penner GB  Steele MA  Aschenbach JR  McBride BW 《Journal of animal science》2011,89(4):1108-1119

Feeding highly fermentable diets to ruminants is one strategy to increase energy intake. The increase in short-chain fatty acid (SCFA) production and reduced ruminal pH associated with highly fermentable diets imposes a challenge to the metabolism and the regulation of intracellular pH homeostasis of ruminal epithelia. The ruminal epithelia respond to these challenges in a coordinated manner. Whereas the enlargement of absorptive surface area is well documented, emerging evidence at the mRNA and transporter and enzyme activity levels indicate that changes in epithelial cell function may be the initial response. It is not surprising that gene expression analysis has identified pathways involved in fatty acid metabolism, ion transport, and intracellular homeostasis to be the pathways dominantly affected during adaptation and after adaptation to a highly fermentable diet. These findings are important because the intraepithelial metabolism of SCFA, particularly butyrate, helps to maintain the concentration gradient between the cytosol and lumen, thereby facilitating absorption. Butyrate metabolism also controls the intracellular availability of butyrate, which is widely regarded as a signaling molecule. Current data indicate that for butyrate metabolism, 3-hydroxy-3-methylglutaryl-CoA synthase and acetyl-CoA acetyltransferase are potential regulatory points with transient up- and downregulation during diet adaptation. In addition to nutrient transport and utilization, genes involved in the maintenance of cellular tight junction integrity and induction of inflammation have been identified as differentially expressed genes during adaptation to highly fermentable diets. This may have important implications on ruminal epithelial barrier function and the inflammatory response often associated with subacute ruminal acidosis. The objective of this review is to summarize ruminal epithelial adaptation to highly fermentable diets focusing on the changes at the enzyme and transporter activity levels, as well as the underlying molecular changes at the mRNA and protein expression levels.  相似文献   

Effect of Kisspeptin on Regulation of Growth Hormone and Luteinizing Hormone in Lactating Dairy Cows     

B. K. Whitlock  J. A. Daniel  R. R. Wilborn  H. S. Maxwell  B. P. Steele  J. L. Sartin 《畜牧与生物技术杂志(英文版)》2011,2(3):131-140

Kisspeptin (KP),a neuroendocrine regulator of reproduction,is hypothesized to be an integrator of metabolism and hormones critical to the regulation of reproduction.Lactation is associated with enhanced growth hormone (GH) responsiveness and reduced fertility.Our study was designed to determine the effects of lactation on KP-stimulated GH and luteinizing hormone (LH) secretion.Five nonlactating and five lactating dairy cows were used in the study.Experiments were conducted with lactating cows at weeks 1,5 and 11 after parturition.The experimental treatments (saline and KP [ 100 and 400 pmol/kg body weight] ) were given intravenously and blood was collected and plasma was stored until later assay to determine concentrations of GH,LH,progesterone and non-esterified fatty acids.We found that neither dose of KP stimulated an increase in GH secretion.The low dose of KP increased (P ＜0.05)LH concentrations only in lactating cows.The higher dose of KP elicited an increase in circulating LH concentrations in both lactating and non-lactating cows.The lower dose of KP increased ( P ＜ 0.05 ) the area under the curve for LH only in cows during week 5 of lactation,and the area under the curve of LH following the highest dose of KP was greater ( P ＜ 0.05 ) in cows during week 5 of lactation than that for the other groups of cows.In summary,lactation status and stage of lactation did not change the sensitivity of the GH system to KP.However,an effect of stage of lactation on KP-stimulated LH secretion was detected in the dairy cows.Study of the KP system during lactation in dairy cows may provide critical insights into the mechanisms for lactation-associated changes in the reproductive axis.  相似文献   

Pheochromocytoma in a white rhinoceros (Ceratotherium simum)     

Bertelsen MF  Steele SL  Gr?ndahl C  Baandrup U 《Journal of zoo and wildlife medicine》2011,42(3):521-523

A 46-yr-old male white rhinoceros (Ceratotherium simum) died during anesthesia following agonal excitation. On postmortem, a well-demarcated 2.5-cm tan mass was identified in the right adrenal gland. Histopathology confirmed the presence of a pheochromocytoma, and elevated levels of epinephrine in serum collected shortly prior to the animal's death, as compared with sera from healthy controls, demonstrated the functional nature of the tumor. Although rare, pheochromocytoma should be considered as a differential diagnosis in cases of suspected hypertension and acute death in rhinos.  相似文献   

Phylogeny and molecular data     

Bode HR  Steele RE 《Science (New York, N.Y.)》1989,243(4890):549-550

  相似文献   

Lamarck and antibody genes     

Steele EJ  Blanden RV 《Science (New York, N.Y.)》2000,288(5475):2318d-2319d

  相似文献   

Sea anemone genome reveals ancestral eumetazoan gene repertoire and genomic organization     

Putnam NH  Srivastava M  Hellsten U  Dirks B  Chapman J  Salamov A  Terry A  Shapiro H  Lindquist E  Kapitonov VV  Jurka J  Genikhovich G  Grigoriev IV  Lucas SM  Steele RE  Finnerty JR  Technau U  Martindale MQ  Rokhsar DS 《Science (New York, N.Y.)》2007,317(5834):86-94

Sea anemones are seemingly primitive animals that, along with corals, jellyfish, and hydras, constitute the oldest eumetazoan phylum, the Cnidaria. Here, we report a comparative analysis of the draft genome of an emerging cnidarian model, the starlet sea anemone Nematostella vectensis. The sea anemone genome is complex, with a gene repertoire, exon-intron structure, and large-scale gene linkage more similar to vertebrates than to flies or nematodes, implying that the genome of the eumetazoan ancestor was similarly complex. Nearly one-fifth of the inferred genes of the ancestor are eumetazoan novelties, which are enriched for animal functions like cell signaling, adhesion, and synaptic transmission. Analysis of diverse pathways suggests that these gene "inventions" along the lineage leading to animals were likely already well integrated with preexisting eukaryotic genes in the eumetazoan progenitor.  相似文献