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Some studies have characterized and evaluated the parasitic load of the Pacific sardine. However, there are few studies related to its physiology and parasites load. This study aimed to evaluate the blood parameters and the abundance of helminth parasites of sardines obtained from two samples from Todos Santos Bay during autumn 2013. The digenea Myosaccium ecaude parasite was the only species registered. Sardines had a prevalence of 28%, an average abundance of 25 and an intensity of 7 parasites. There were no statistically significant differences (P > 0.05) in most of the analyzed blood parameters (red blood cell count, hematocrit, leukocyte cellular differentiation, mean corpuscular volume, total protein, glucose, alanine aminotransferase, osmotic pressure, Na, K, and pH) of fish with and without parasites, except in white blood cell count and in Ca concentration that showed a marked decrease. The relationship between parasite abundance and blood parameters, based on the results of this study, it is not clear due to the low parasitic load. [ABSTRACT FROM AUTHOR]

Fish mariculture from the genus Seriola spp. can present high mortalities due to parasites. In Mexico, the mortality yellowtail Seriola dorsalis caused by parasites is low, and there are no reports of massive mortality events. However, as the aquaculture activity of yellowtail intensifies, parasites will be increasingly conspicuous. Therefore, the present study is an aim to know S. dorsalis's susceptibility to a monogenean infection mixed under RAS experimental conditions and their intensity and spatial distribution on the skin and gills. In this study, a parasitic mix induction was performed using two monogenean species such as Zeuxapta seriolae and Benedenia seriolae besides the Amyloodinium ocellatum, a dinoflagellate that was naturally presented. At the end of the experiment after 45 days, B. seriolae prevalence was 100% with a mean intensity of 122 parasites and showed a preference for the head and body of the fish. Zeuxapta seriolae prevalence was 100% with a mean intensity of 40 parasites preferentially found in the second branchial arch. In the case of A. ocellatum prevalence was of 100% with a mean intensity greater than 200 trophozoites per fish. The fish mortality reached 90% at the end of the experiment. During the infection, the fish weight decreased a 14% at the end of the experiment. Therefore, it will be necessary to carry out prophylactic and control strategies, to reduce the impact of these parasites under culture conditions. [ABSTRACT FROM AUTHOR]

An 18-week feeding trial was conducted to estimate the optimum dietary pantothenic acid (PA) requirement for juvenile of Lutjanus guttatus. Seven isoproteic and isocaloric practical diets were formulated containing graded levels of pantothenic acid (PA) 2.57, 31.97, 47.91, 63.79, 76.83, 103.15 and 121.91 mg kg-1. Triplicate groups of 15 fish, with an initial weight of 10.2 ± 1.4 g, were cultured in 21 glass-fiber tanks and received each diet at random three times daily to apparent satiety. Results showed that the weight gain of fish fed diet 2.57 mg kg-1 PA was significantly less than the weight gain of fish fed diets containing greater quantities of PA. However, no significant differences were observed in the weight gain of the fish fed diets containing between 31.97 to 121.91 mg kg-1 PA. External signs of deficiency in the fish of diet (2.57 mg kg-1 PA) included caudal fin erosion, desquamation of the skin, hemorrhages in the body and fins, lethargy and 80% mortality rate were recorded. Hematological parameters indicated that there was no clear reduction of hemoglobin with PA in the diets. The dietary PA requirement to attain maximum growth rate, good survival, and the absence of external injuries range between 40.10 and 44.29 mg kg-1. [ABSTRACT FROM AUTHOR]