The Effect of Size and Diet on Gonad Production by the Chilean Sea Urchin Loxechinus albus

Conadal production was studied in Loxechinus albus (Molina, 1782) maintained in cages suspended from a long-line in the Estero Castro, Chiloé for 3 mo during the austral summer. The sea urchins were fed either an artificial diet or a natural diet consisting of the macroalgae Macrocystis pyrifera and Ulva sp. Both diets were tested for four size ranges: 40–45, 50–55, 60–65 and 70–75 mm diameter. For all four size ranges, highest gonad production was with the artificial diet. Gonad production was greatest in the 40–45 mm individuals with an increase of about 1,400% and 750% in the wet weight of gonads in individuals fed the artificial and natural diet, respectively. With the three other size ranges, the increase was nearly 100% with the artificial diet and nearly 0% with the natural diet The gonad index showed similar patterns, being highest in the smallest individuals. Small individuals fed the artificial diet would provide the most cost effective aquaculture as production is best. It is not necessary to grow L. albus to the minimal legal size for fisheries (70-mm diameter) for cost effective gonad production.     

Effect of salicylic acid treatment on tomato plant physiology and tolerance to potato virus X infection

Salicylic acid (SA) is an inducer of systemic acquired resistance (SAR) and could be a potential candidate in the control of plant virus diseases. In this study we assayed under controlled conditions the potential effect of three doses of exogenous SA treatment on tomato plants infected with Potato virus X (PVX) and measured their effects on: different physiological parameters (gas exchange, stable isotopes, chlorophyll content), the activation of secondary metabolism, viral accumulation and induction of the expression of pathogenesis-related proteins (PRs) such as ß-1, 3-glucanase (PR2) and chitinase (PR3). SA treatment increased the expression of PR2, the activity of phenylalanine ammonia lyase (PAL) and the concentration of antioxidant compounds at 7 days post-treatment. Earlier expression of PR3 compared to PR2 was observed. SA treatment delayed the detection of PVX by ELISA in uninoculated leaves of mechanically infected tomato plants. Although the effect of PVX infection on physiological parameters was weak, moderate SA treatments showed enhanced photosynthesis, particularly for infected plants. The results obtained confirm that SA promotes major changes in the induction of resistance in tomato plants and suggest that treatment with exogenous SA could be considered to reduce the infections caused by PVX.     

Effect of site and storage conditions on quality of industrial fresh pepper

The commercial expansion of roasted pepper as a high market value product have made that the period of time in which canning industries process the fresh pepper fruits needs to be extended. Fresh sweet pepper (Capsicum annuum L.) destined for industry grown in different sites was cold stored in order to analyse the effect of different sites and storage conditions on the quality of the product at harvest and during storage. Storage during 10 days at 8 °C was the best storage condition to improve quality of pepper destined for industry, because colour was improved, weight loss (1–1.6%) was lower than maximum permissible and decay incidence was only between 0% and 2.3%. Harvest should be delayed until pepper reaches the red state in order to increase the quality of the fruit. However, these results suggest that pepper growers should assure a high content of Ca (>0.6 g kg⁻¹) in the soil to avoid a high incidence of decay during storage when a late harvest is needed to guarantee the enhancement of colour in pepper fruit destined for industry. These storage conditions are in accordance with those found to improve the sensory quality of roasted pepper.     

Aflatoxin B<Subscript>1</Subscript> (AFB<Subscript>1</Subscript>) reduces growth performance,physiological response,and disease resistance in Tra catfish (<Emphasis Type="Italic">Pangasius hypophthalmus</Emphasis>)

Triplicate groups of one hundred Tra catfish (8 g?±?0.2) were fed seven test diets containing increasing levels of AFB₁ (0, 50, 100, 250, 500, and 1000 μg AFB₁ kg^?1). Additionally Mycofix® Secure was added at 1.5% to one diet containing 500 μg AFB₁ kg^?1. Results showed that Tra catfish are sensitive to AFB₁. Reduction in weight gain (P?<?0.05) was observed for fish fed 50 μg AFB₁ kg^?1 and declined further with increasing levels of AFB₁ in the diets. Fish fed diets contaminated with 500 and 1000 μg AFB₁ kg^?1 showed increased (P?>?0.05) hepatosomatic index (HIS), while an increase in adipose somatic index (ASI) was observed in fish fed 50 μg AFB₁ kg^?1 and above when compared to the control and Mycofix® diets. After 12 weeks, blood serum analysis revealed higher alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in fish fed the 50, 100, and 250 μg AFB₁ kg^?1 suggesting occurrence of liver damage. Disease resistance of fish exposed to Edwardsiella ictaluri was also compromised by the presence of AFB₁ in the feed and was directly related to the contamination level. Seven days after Edwardsiella ictaluri exposure, survival rates were 50, 41.7, 31.7, and 8.3% for fish fed control, 50, 100, and 250 μg AFB₁ kg^?1, respectively. This trial shows that AFB₁ at a level of 50 μg AFB₁ kg^?1 and above can affect fish performance and disease resistance. Application of an effective mycotoxin management in the feed seems to be useful to prevent the negative effects of AFB₁.     

Diarrhoea during lactation_Infection in pigs due to Rotavirus

轮状病毒是影响新生仔猪的几种重要的肠道致病因子之一.它们可导致仔猪爆发肠胃炎. 1病原学 轮状病毒是一种RNA病毒,其特点是有一个二十面的衣壳结构(图1),衣壳外无覆盖物.研究表明,该病毒至少有7种不同的血清群(A、B、C、D、E、F和G血清群).     

Diarrhoea during Lactation:Coccidiosis

1生活周期 了解猪等孢子球虫的生活周期对于了解球虫病的诊断方法、治疗手段和预防措施是非常重要的.在这个生活周期中,猪等孢子球虫有一个环境生活阶段(卵囊),在条件适当的情况下,卵囊的生活力可以保持长达一年,这一特性有利于该感染在产仔栏中的持续存在.     

Morphometric analysis of the corneal endothelium of Yacare caiman (Caiman yacare) using scanning electron microscopy

The objective of this study was to examine the endothelial surface morphology and to perform morphometric analysis of the corneal endothelial cells of Yacare caiman (Caiman yacare) using scanning electron microscopy. Morphometric analysis with regard to polygonality, mean cell area, cell density and coefficient of variation of mean cell area was performed. Cell areas were measured using image analysis software. The normal corneal endothelium of Yacare caiman consisted of polygonal cells of uniform size and shape with interdigitations of the cell borders. Microvilli appeared as protrusions on the cellular surface. The average cell area was 270 +/- 24 microm(2) and the endothelial cell density was 3704 +/- 324 cells/mm(2). The coefficient of variation of cell area was 0.22. This study demonstrates that the Yacare caiman corneal endothelium is similar to those described in other vertebrates.     

水产饲料中的霉菌霉素

霉菌毒素是霉菌产生的次级代谢产物.霉菌在农作物收获前、收获后及运输和仓储的过程中都可生长并产生霉菌毒素.