Our objective was to assess the quality of eggs and juvenile of Nile tilapia (Oreochromis niloticus) from broodstock of three commercial hatcheries (Hl, H2, and H3). Larval weight was significantly ...higher for H2 and H3 hatcheries (P < 0.05). After 45-day growth, weight of juveniles of H2 was higher, while specific growth rate was significantly higher for H1 and H2 (P < 0.05). After the ammonia stress test, no significant differences in mortality were found among larvae from the three hatcheries, although a positive relationship between carbohydrate content in eggs and juvenile mortality was observed (P < 0.05). After the salinity stress test, the lowest and highest mortality (P < 0.05) occurred respectively in tilapia larvae from the H1 (24.2%) and H3 (57.8%) hatcheries. We concluded that egg quality was not affected by tilapia broodstock from the three hatcheries studied, but differences were obtained for growth performance, carbohydrate content, and survival of juveniles when exposed to the salinity stress test. These three indexes should be considered as potential juvenile quality criteria for tilapia.
Environmental contaminants endanger human health and non-target organisms such as crocodiles (Crocodylus acutus) that live in aquatic bodies surrounding agricultural areas. Due to their intrinsic ...characteristics, these organisms could be bioaccumulating and transmitting organochlorine pesticides (OCs) to their eggs. The objectives of this study were to determine the OCs in infertile eggs of C. acutus from Sinaloa and their correlation with the morphometric characteristics (MC), and to perform a preliminary estimate of the ecological risk due to the presence of pesticides using the PERPEST model. In June 2022, 76 infertile eggs (Ie) were collected: 57 from wild areas (Wa) and 19 from a crocodile farm (CSMf). Determination of OC in Ie was performed according to the USEPA method 8081b, modified. The observed percentages of Ie in Wa were 31.48% and 21.33% in CSMf. Twenty OCs were detected in the Ie, where dieldrin recorded the highest average concentration in Wa (6542.6 ng/g), and endosulfan-II in the CSMf (2172.8 ng/g). Bad negative and positive correlations were observed between OCs and MC, standing out the correlations between endosulfan-II and %Ie (-0.688) in the Wa, Cedritos drain, and between endrin and the weight of Ie (0.786) of the CSMf. The evaluation of the ecological risks of the aquatic environment due to the presence of OCs follow the sequence cyclodienes > aromatic > alicyclic hydrocarbons. A potential risk to the endocrine health of the species C. acutus was observed. Crocodiles are excellent biological models for monitoring the effects of OCs.
The algae Ulva lactuca and Gracilaria parvispora are abundant in the Gulf of California, rich in nutrients, and may be used as a source of protein in balanced diets for shrimp. This study tests ...whether their meal, as a partial inclusion in diets for juvenile Litopenaeus vannamei, is feasible. Percentages of inclusion were 5, 10, and 15 %. Results showed that final weight, weight gain, and specific growth rate varied significantly among diets (P < 0.05). There were significant differences in growth among the trials of amount of inclusion of meal when using U. lactuca (P < 0.05), and no significant differences among the trials when using G. parvispora (P > 0.05). In general, better results were obtained when using G. parvispora compared with U. lactuca. When compared to the control diet (without inclusion), diets that included 10 and 15 % U. lactuca meal yielded a significantly lower growth (P < 0.05), but no significant differences were detected when using U. lactuca 5 % meal (P > 0.05), suggesting the feasibility of inclusion to this limited percentage. No significant differences were detected between the control and the three treatments with G. parvispora, suggesting the possibility of using higher percentages of inclusion. We conclude that both seaweeds may be used as a component in preparing feed for juvenile L. vannamei.
This article proposes an enhanced and less painful procedure to eliminate the flow of hormones from the X organ sinus gland in adult Macrobrachium americanum. Three groups and two controls were ...analyzed to determine the amount of stress caused by the following: (1) unilateral eyestalk ablation, (2) unilateral eyestalk ablation and covering to allow coagulation, and (3) ligation at the base of the eyestalk. Each group was divided into two subgroups to analyze the effect of treatment with and without Xylocaine. For males and females, the control groups were only manipulated but not ablated. The trauma caused by the treatments in M. americanum was reflected by behaviors related to pain, including tail flicking as a reflex response to allow escape and rubbing the affected area. In addition, we also observed alterations in five behaviors. Four behaviors were directly related to pain and discomfort – non-sheltering, disorientation, recoil and stooping – and the fifth, feeding behavior, was related to the hormonal disorder caused by the extirpation of the X organ sinus gland. The variables that were directly affected by the treatments were bleeding, ligating and hormonal state. The treatment that caused the most significant negative stimulus was ligation. The animals in the ligation group exhibited up to 50% more flicking, 90% more rubbing, 50% more disorientation, and 80% more recoil than the animals in the other subgroups. Ablation without covering to allow coagulation was a moderate significant negative stimulus. Finally, the treatment with the least negative stimulus was the treatment of females using anesthetic and ablation followed by covering to allow coagulation. This subgroup exhibited only 20% more flicking and 20% more rubbing than controls, and only 30% were not sheltered. These prawns also did not show disorientation, recoil or stooping.
Our objective was to assess the quality of eggs and juvenile of Nile tilapia (Oreochromis niloticus) from broodstock of three commercial hatcheries (H1, H2, and H3). Larval weight was significantly ...higher for H2 and H3 hatcheries (P < 0.05). After 45-day growth, weight of juveniles of H2 was higher, while specific growth rate was significantly higher for H1 and H2 (P < 0.05). After the ammonia stress test, no significant differences in mortality were found among larvae from the three hatcheries, although a positive relationship between carbohydrate content in eggs and juvenile mortality was observed (P < 0.05). After the salinity stress test, the lowest and highest mortality (P < 0.05) occurred respectively in tilapia larvae from the H1 (24.2%) and H3 (57.8%) hatcheries. We concluded that egg quality was not affected by tilapia broodstock from the three hatcheries studied, but differences were obtained for growth performance, carbohydrate content, and survival of juveniles when exposed to the salinity stress test. These three indexes should be considered as potential juvenile quality criteria for tilapia.
Desarrollar un plan de fortalecimiento del control de la mala-ria hacia su eliminación. En 2009, bajo la coordinación del Instituto Nacional de Salud Pública, se integró un equipo técnico ...transdisciplinario para hacer un diagnóstico situacional de la malaria y de los programa de control y para la selección de prácticas efectivas de intervención que serían incorporadas al plan, en el marco de un ejercicio de teoría de cambio. Se establecieron criterios de estratificación de las localidades con base en sus condiciones de transmisión. Se identificaron limitaciones estructurales y operativas de los programas de control. Se elaboró un plan de intervenciones para mejorar la cobertura de vigilancia epidemiológica, intervenciones antimaláricas y diagnóstico y tratamiento oportunos de casos. El plan delinea con fases progresivas de implementación: reorganización, intensificación de intervenciones y evaluación de la factibilidad de eliminación. La adopción de un plan estratégico único brindará lineamientos y elementos administrativos para conformar un sistema que coordine las actividades de los programas nacionales de control y facilite la eliminación de la malaria en la región.
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