Measurement of endogenous amino acid losses in poultry

1. Ileal endogenous amino acid losses were determined in broiler chickens and in cannulated cross‐bred layer strain cockerels using either a nitrogen‐free diet, regression analysis or a 48 h fast.

2. Endogenous amino acid flows to the ileum in fasted cockerels were significantly lower than those obtained both by feeding the nitrogen‐free diet, and from regression analysis in either broilers or cockerels. Regression analysis gave the highest flows.

3. The apparent digestibility coefficients of amino acids in a diet containing 200 g/kg crude protein were lower in broilers (0.84) than in cockerels (0.88). When corrected, by regression analysis, for the contribution of endogenous amino acids, the true digestibility coefficients became 0.90 and 0.92 respectively.     

Hanging Drop Monoculture for Selection of Optimal Antioxidants During In Vitro Maturation of Porcine Oocytes

We analysed the effect of three antioxidants that have different functional mechanisms on the in vitro maturation (IVM) of porcine oocytes. Single oocyte monoculture using the hanging drop (HD) system has some advantages such as improving analysis efficiency brought by the smaller number of samples than the number of oocytes cultured in one drop. Direct effects of ligands on single oocytes could also be detected without considering the effects of paracrine factors from other oocytes. After 22 h of pre‐culture, denuded oocytes were cultured for 22 h with 0.01 and 0.1 μg/ml of L‐carnitine (LC), lactoferrin (LF) or sulforaphane (SF) in the presence/non‐presence of oxidant stress induced by H₂O₂ supplementation to evaluate the reducing effects against oxidative stress on nuclear maturation. As a result, compared with LC and SF, LF showed effective reduction in oxidative stress at a lower concentration (0.01 μg/ml), suggesting that LF is a more effective antioxidant in porcine oocyte IVM. Additionally, LF also increased maturation rate even in culture without H₂O₂. Our results clearly suggest that the HD monoculture system is useful for screening the substances that affect porcine oocyte culture.     

Assessment of endothelium-dependent vasodilation in equine digital resistance vessels

Haemodynamic disturbances leading to ischaemia and reperfusion injury of the digit are thought to be involved in the pathophysiology of acute equine laminitis. Identification of physiological regulators of blood flow through the equine digit is important in identifying factors, which may predispose animals to laminitis. A method was developed to assess endothelium-dependent responses of the isolated Krebs-perfused equine digit by co-administration of 5-hydroxytryptamine (5-HT) with vasodilator agents, carbachol (CCh), bradykinin (BK) and substance P (SP). Bolus co-administration of CCh (0.02-2 micromol), BK and SP (0.02-0.2 nmol), caused inhibition of the 5-HT pressor response by 50-60%. The vasodilator responses were abolished by the detergent, CHAPS, indicating endothelium dependency; whereas vasoconstrictor responses to 5-HT were potentiated. CCh-induced relaxation was significantly reduced by the nitric oxide synthase inhibitor L-NAME (79.7 +/- 3.4% inhibition), whereas a large proportion of BK and SP-induced relaxation remained (34.1 +/- 6.3% and 33.6 +/- 5.3% inhibition). L-NAME potentiated vasoconstrictor responses to 5-HT. In conclusion, this study demonstrates that endothelium-derived NO modulates the response to vasoconstrictors such as 5-HT and is likely to be an important regulator of blood flow in the digital resistance vascular bed. Other factor(s) released by the endothelium are also important in regulating blood flow, whose identity remains to be established.     

Ovarian cysts in MRL/MpJ mice originate from rete ovarii

In MRL mice aged more than 1 year, but not in C57BL/6 mice, ovaries had grossly visible cysts presenting unilaterally or bilaterally. Postnatally, all MRL mice developed ovarian cysts by 8 months of age. Observations by light microscopy, including lectin histochemistry, indicated that the cysts sometimes included papillomatous tissues located at the hilar region and were similar to the rete ovarii system, but not to follicles. Two types of epithelial cells, ciliated and non-ciliated, were arranged on the cysts, in which both cell types had many microvilli projecting in various directions and random ramifications in the cystic lumen. These characteristics suggest that ovarian cysts developing in MRL mice originate mostly from the rete ovarii. Cysts derived from the rete ovarii at 8 months of age were histologically detected in all C3H mice as well as MRL mice, with variable incidence in ICR, AKR, CBA/N and ddY, and none in C57L/6, DBA/2, BALB and A/J mice. However, measurement of the maximum diameters of the ovarian cysts indicated that MRL mice regularly possessed the largest cysts visible to the naked eye. This is the first report of ovarian cysts in this inbred strain, suggesting that ovarian cysts in MRL mice appear with stable incidence and development.     

Helping students learn veterinary physiology through the use of concept maps

Concept maps have become a ubiquitous tool in education in the last 20 years and are used extensively to teach scientific concepts. A concept map is a tool learners can use to organize information about a topic in terms of key concepts and the relationships among them. As a graphical representation, the map provides an overall picture of a particular concept or topic. This article describes how we have used concept maps to teach physiology to veterinary medical and veterinary technician students enrolled in our on-campus and distance-learning programs.     

Characterisation of European varieties of triticale with special emphasis on the ability of plant phytase to improve phytate phosphorus availability to chickens

1. A total of 30 varieties and selection lines of triticale grown under similar conditions were characterised. Thousand grain weight, specific weight, Hagberg falling number and N were 50.2 +/- 5.0 g, 72.4 +/- 2.1 kg/hl, 96 +/- 48 s and 16.1 +/- 0.11 g/kg, respectively. 2. Mean phosphorus (P) concentration was 2.86 +/- 0.31 g/kg, of which 77% was of phytic origin. Mean phytase activity was 1018 +/- 319 phytase units (PU)/kg. A genotypic effect on phytase activity was detected amongst 5 varieties studied out of 30. Potential and real applied viscosities were positively correlated and mean values were 3.53 +/- 0.66 and 2.15 +/- 0.31 ml/g, respectively. 3. The efficacy of plant phytase in improving P availability was assessed in chickens up to 3 weeks of age. Growth performance and bone ash concentration were compared in birds given either a maize (450 g/kg) and soybean meal (230 g/kg) phosphorus deficient diet containing 3.5 g P/kg, this basal diet supplemented with 1 or 2 g P/kg as monocalcium phosphate (MCP) or triticale (450 g/kg) and soybean meal (230 g/kg) diets containing 3.2 to 3.8 g P/kg with no MCP. To achieve graded levels of phytase activity, 4 varieties of triticale, intact or in which phytase was denaturated by heat treatment, were used. Estimated metabolisable energy, protein, amino acids and calcium concentrations were similar in all diets. 4. Phytase activity in the triticale-based diets ranged between 135 and 1390 PU/kg. Growth performance and bone ash were responsive to plant phytase and to MCP. Non-linear models of these responses were adjusted with the best fit for bone ash parameters. The values of 250, 500 and 1000 PU of plant phytase were estimated to be equivalent to 0.46, 0.67 and 0.81 g P as MCP, respectively.     

Effects of Exogenous Glycine Betaine on the Physiological Characteristics in Medicago sativa Seedlings under Low-temperature Stress北大核心CSCD

In this study,the 'Ganong 5th' alfalfa (Medicago sativa L.) was used as experimental material,and two application methods (leaf application,root application) and six exogenous betaine concentrations (0,10,20,30,40 and 50 mmol·L-1) were used to treat the seedlings of alfalfa. Plant growth and related physiological indexes were measured after 7 days of low temperature (4?) stress,and the physiological mechanism of exogenous betaine to alleviate the low temperature stress of alfalfa was explored. The results showed that exogenous GB alleviated the loss of plant height,root length,leaf dry weight,root dry weight and chlorophyll content,and increase the content of soluble sugar (SS) and free proline (Pro),and reduced the increase in leaf relative membrane permeability and MDA content. Exogenous GB increased antioxidant enzyme activities and non-enzymatic antioxidant content. And also,exogenous GB enhanced the osmotic adjustment capacity of the plant by increasing endogenous GB accumulation and BADH activity. These results indicated that exogenous GB enhanced the resistance of Medicago sativa to low-temperature stress under low temperature adjustment. The membership function analysis indicated that spraying 30 mmol·L-1 GB on the leaves and spraying 40 mmol·L-1 GB on the roots had the best effect on alleviating the low-temperature stress of alfalfa seedlings. © 2019 Ｊｏｕｒｎａｌ ｏｆ Ｒｅｆｒｉｇｅｒａｔｉｏｎ. All rights reserved.     

Effect of several supplemental Chinese herbs additives on rumen fermentation, antioxidant function and nutrient digestibility in sheep

Two experiments were carried out in this study. Experiment 1 was conducted to examine the effects of several supplemental Chinese herbs on antioxidant function and slaughtered body weight in sheep. Results indicated that Fructus Ligustri Lucidi supplementation improved the blood antioxidant function [higher concentration of glutathione reductase (GR), superoxide dismutase and lower concentration of malondialdehyde] and slaughtered body weight in sheep (p < 0.05). Experiment 2 was conducted to investigate the effect of Fructus Ligustri Lucidi extract (FLLE) on rumen fermentation and nutrient digestibility in sheep. Four levels of FLLE treatments, i.e. 0, 100, 300 and 500 mg/kg dry matter (DM), were used in this part. Addition of FLLE at 300 or 500 mg/kg DM increased total volatile fatty acid (VFA) concentration and propionate proportion, decreased ammonia-N concentration in the ruminal fluid, reduced blood urea nitrogen concentration at 2, 4, 6 and 8 h after morning feeding (p < 0.05). Addition of FLLE at all dosages had no effect on ruminal pH value and acetate concentration at all sampling time points in sheep (p > 0.05). Dynamic degradation coefficient c of maize DM was significantly increased by supplementing FLLE at 300 or 500 mg/kg DM (p < 0.05). Fructus Ligustri Lucidi extract addition had no effect on degradation coefficients a, b, c of DM and nitrogen of soybean meal; a, b of maize DM; a, b, c of maize nitrogen; and a, b, c of neutral detergent fibre (NDF) and acid detergent fibre (ADF) of Chinese wildrye (p > 0.05). Addition of FLLE at 300 or 500 mg/kg DM increased DM and organic matter digestibility of diet (p < 0.05). Fructus Ligustri Lucidi extract addition had no effect on digestibility of diet's NDF, ADF and crude protein (p > 0.05). From the aforementioned results, it is indicated that FLLE improved antioxidant status and slaughtered body weight. Fructus Ligustri Lucidi extract addition has capability to modulate rumen fermentation, increase the maize degradation rate, total volatile fatty acid concentration and propionate proportion in sheep.