Cynthia Montoya Martinez

Objective: To evaluate some reproductive aspects of D. latifrons and the nutritional quality of its eggs. Design/methods/approach: Eighty-two fish were randomly collected (August 2021), and their sex, length, weight, somatic indices, Fulton condition index (K), proximate composition, and amino acid and lipid composition (fatty acids) of the gonads were determined. Results: Of the total specimens collected, 62% were females; length and weight values were higher in males, but their gonadosomatic index (GSI) was lower than in females. Somatic indices did not show differences between different weight ranges. In the roe of D. latifrons, the average proximate composition was 24.3% protein and 8.5% lipids. The most abundant essential amino acids were leucine and lysine. Linoleic acid (C18:2n6) was the fatty acid with the highest concentration. Limitations/implications: It is necessary to complement the analysis of the amino acid and fatty acid profile of the roe in wild organisms to relate the changes caused by balanced feed. Findings/conclusions: This study shows that the D. latifrons roe is a good source of amino acids and PUFA. Keywords: proximate composition, fatty acids, essential amino acids Objective: To evaluate some reproductive aspects of D. latifrons and the nutritional quality of its eggs. Design/methods/approach: Eighty-two fish were randomly collected (August 2021), and their sex, length, weight, somatic indices, Fulton condition index (K), proximate composition, and amino acid and lipid composition (fatty acids) of the gonads were determined. Results: Of the total specimens collected, 62% were females; length and weight values were higher in males, but their gonadosomatic index (GSI) was lower than in females. Somatic indices did not show differences between different weight ranges. In the roe of D. latifrons, the average proximate composition was 24.3% protein and 8.5% lipids. The most abundant essential amino acids were leucine and lysine. Linoleic acid (C18:2n6) was the fatty acid with the highest concentration. Limitations/implications: It is necessary to complement the analysis of the amino acid and fatty acid profile of the roe in wild organisms to relate the changes caused by balanced feed. Findings/conclusions: This study shows that the D. latifrons roe is a good source of amino acids and PUFA.

Objective: To determine the protein nutritional requirements in juvenile axolotls, for this purpose, four isocaloric diets (8 % lipids) with 30, 35, 30 and 45 % protein were prepared. Design / methodology / approach: Six axolotls were used per test, during a period of 81 days. The diets were prepared using fishmeal as a protein source and fish oil as a lipid source. The feed was supplied every 48 hours with 4% of the weight of the biomass of organisms per experimental reservoir. Four biometries were performed throughout the experiment and growth parameters were determined: height, weight gained per day, specific growth rate, survival, Fulton's K, and protein efficiency rate. The digestibility of each of the diets was also determined. Results: There were significant differences (p> 0.05) in the growth and survival of the axolotls, the diet with 45% protein showed the best growth results. Limitations / Implications: No more protein levels could be tested, due to the number of organisms available for bioassays. Findings / conclusions: Diets for A. mexicanum containing 45% protein level promote good development and survival. This allows for improved cultivation and management plans for the species.

The present work is a review of the literature on the native Mexican fish Dormitator latifrons. The aim is to contribute to the integration and systematization of current knowledge to make it easier to identify existing knowledge gaps and breakthroghs Moreover, promote the successful cultivation and protection of this species whose consumption is increasing in Latin America. A review of the articles related to D. latifrons published in international and regional databases was carried out. The articles reviewed focus on taxonomy and systematics, phylogenetic, geographic distribution, ecology, physiology, reproduction, development, pathology, health, and the technologies used to cultivate this fish species. The conclusion is that, even though the cultivation of D. latifrons is of commercial interest in some countries, there are still significant gaps in our knowledge of biology and, consequently, the domestication potential of the species. Filling these gaps will require systematic research efforts on protecting natural populations and improving mass cultivation techniques.