Elias Gustavo Figueroa

• PhD, MSc, Profesor
• Researcher at Temuco Catholic University

The COVID-19 pandemic has significantly impacted tilapia farming worldwide, causing a notable decline in production and marketing since 2020. To address post-pandemic challenges, such as antibiotic resistance and the need for sustainable feed enhancement strategies, probiotics have emerged as a promising solution. However, systematic evaluation bas...

Recent projections suggest that food security may face threats due to climate change and population growth. Global warming is altering ocean temperatures, impacting productivity and aquatic ecosystems. This review delves into the impact of heat stress on fish aquaculture, focusing on the neuroendocrine system, controlled by the hypothalamic-pituita...

To meet growing fish demand, aquaculture must develop sustainable, cost‐effective, and high‐performance fish feed formulations for industry advancement. Plant‐based lipids are a viable alternative to forage fish ingredients in finfish diets. However, most plant‐derived lipids lack long‐chain polyunsaturated fatty acids (LC‐PUFA) like EPA and DHA, w...

The chorion is an acellular envelope that surrounds fish oocytes and embryos, playing a crucial role in protection against environmental factors until hatching. In salmonids, several chorion malformations have been documented, including white-spotted (disc-like) chorion. This study focused on investigating the ultrastructural modifications of the c...

Highlights Cryopreservation generates ice recrystallization. D. antarctica apoplastic proteins show antifreeze activity. PMI of S. salar sperm can be maintained with AFPs. High MMP of sperm increases with AFPs. D. antarctica apoplastic proteins act as nonpermeable cryoprotectants. Abstract Antifreeze proteins (AFPs) are natural biomolecules found...

Simple Summary Galaxias maculatus plays an important ecological and socioeconomic role in Chile. We determine the sex ratio, sexual maturity stages, gonadosomatic index, spawning period, type and frequency of spawning, and fecundity under experimental culture. The sex ratio was close to 1:1. First sexual maturity was reached at one year of age in 5...

The number of people with dietary restrictions on dairy products has increased significantly due to lactose intolerance/allergy or adoption of vegan diets. Organic acid-producing probiotics have been used in fermented beverages, such as those based on soy, with good results. Such molecules have in fact been described for their role in sensory analy...

Data regarding the pandemic's impact on tilapia culture remain limited, but it is known that there was a significant decline in production and marketing since 2020. The post-pandemic challenges confronting tilapia farming necessitate prompt solutions, encompassing the management of bacterial infections and the adoption of more advanced technologies...

In addition to their use in human medicine, antimicrobials are also used in food animals and aquaculture, and their use can be categorized as therapeutic against bacterial infections. The use of antimicrobials in aquaculture may involve a broad environmental application that affects a wide variety of bacteria, promoting the spread of bacterial resi...

Motility is a key in spermatozoon function, determining semen quality and fertilizing capacity. Motility in fish spermatozoa occurs when they are diluted in a swimming solution, the adequacy of which is determined by factors which vary by species. Spermatozoon motility rate and velocity, as well as the duration of the motility period, are influence...

One of the most astonishing examples of chromatin remodelling occurs during the maturation of male germ cells, where changes in protein structure, as well as chromatin compaction, take place. During the post-meiotic formation of sperm (spermiogenesis), chromatin appears super-condensed, and transcriptionally inactive, allowing for a more hydrodynam...

The present study investigated the spermatological characteristics of raw semen of Lebranche mullet (Mugil liza), namely pH, and sperm density, and motility; and subsequently evaluated the effects of different times of exposure to cryoprotectants, and the application of an ultra-rapid freezing protocol, on sperm motility and plasma membrane integri...

The regulation of sperm motility is controlled by several variables, including mainly ion concentrations. In fish, Ca2+ concentrations play an important role in the regulation of sperm motility, and several reports highlight the importance of certain Ca2+ channels in the regulation of this cell function. CatSper is a calcium channel scarcely studie...

Fish sperm quality assessment is an essential process for commercial production. The goal of this study was to evaluate the quality of fresh milt of farmed coho salmon using a functional and structural approach. A total of 37 males were used to determined parameters such as sperm concentration, pH and osmolality of seminal plasma, viability, mitoch...

Sperm cryopreservation is an important tool for reproductive management; however, it has not been possible to perform this procedure for coho salmon. This study was designed to assess the effect of cryopreservation on sperm functional parameters, oxidative stress markers and fertilizing capacity of coho salmon. Eight extenders were tested, consisti...

Calcium is a prerequisite factor for triggering the sperm activation in salmonids. The aim of this study was to test different concentrations of Ca²⁺ on sperm motility activation and fertility of rainbow trout (Oncorhynchus mykiss). Semen samples activated with calcium free activator (0.0 mM) and increasing concentrations of CaCl2 (6.3, 7.9, 9.5 an...

Reactive oxygen species (ROS) have been proposed as one of the main causes of the impairment of fish spermatozoa integrity and functionality during cryopreservation. The high content of unsaturated fatty acids in sperm cells and the low antioxidant capacity of diluted semen are key factors in making sperm cells susceptible to ROS attacks. For this...

Short-term storage of semen is a necessary key procedure in fish; it allows maximizing the use of gametes. Nevertheless, sperm quality decreases during storage has been associated with oxidative stress damage due to an increase in reactive oxygen species (ROS) during storage. This study was designed to optimize a short-term storage protocol for Coh...

The aim of this study was to evaluate effects of selection using the Percoll density gradient method on motility, mitochondrial membrane potential (ΔΨMit) and fertility in a subpopulation of testicular spermatozoa obtained from Atlantic salmon (Salmo salar). Samples were divided into three groups: Control (C), T1 (45/90% Percoll®) and T2 (45/60% Pe...

Among all the Ca2+ channels, CatSper channels have been one of the most studied in sperm of different species due to their demonstrated role in the fertilization process. In fish sperm, the calcium channel plays a key role in sperm activation. However, the functionality of the CatSper channels has not been studied in any of the fish species. For th...

To improve bacteriocin-like inhibitory substance (BLIS) production by Pediococcus pentosaceus ATCC 43200, the influence of pH as well as the addition of sugars—either prebiotic (inulin) or not (sucrose)—on its metabolism were investigated. This strain was grown at pH 5.0 or 6.0 either in glucose-based MRS medium (control) or after addition of 0.5,...

Storage of refrigerated semen is a simple and inexpensive procedure that can facilitate the management and reproduction programmes in aquaculture and allows to store semen for in vitro reproduction, quality analyses, hatchery production support, selective in vitro breeding, disease diagnosis, transportation, cryopreservation and advanced molecular...

The development of cryopreservation techniques has led to important changes in animal reproductive biotechnology. However, these techniques are associated with cellular and molecular damage, affecting the mitochondrial function and quality of spermatozoa; moreover studies in fish are limited. In this work, the effects of cryopreservation on ultrast...

Sperm motility in fish with external fertilization is critical for reproductive efficiency in aquaculture, especially in salmonids. Gamete preservation techniques, such as cryopreservation, however, reduce sperm motility and fertilizing capacity. Very few studies have addressed cryodamage from energetic and cell signalling approaches. In this study...

In this study, the morphology and ultrastructure of Eleginops maclovinus spermatozoa were characterized through scanning and electron microscopy. Findings revealed that E. maclovinus spermatozoa can be differentiated into three major parts: a spherical head without acrosome (typical for externally fertilizing teleost), a midpiece containing 2–5 sph...

There is no information about the characteristics of early cleavage in the Patagonian blennie ( Eleginops maclovinus ), which can be used as a diagnostic tool for embryo quality. The purpose of this investigation, therefore, was to characterize the first blastomeres of E. maclovinus morphologically. Of a ‘pool’ of incubated eggs at 10.7 ± 0.5°C, 10...

Patagonian blenny (E. maclovinus) is a marine species recently placed in captivity and which are potentially farmable. Understanding and improving its sperm capacity to withstand short-term storage conditions is a key element of initiating an artificial propagation program for this species. The aim of this study is to evaluate the ultrastructure an...

In this research we evaluated simple aspects of the sperm biology of Genypterus blacodes, in particular assessing the effects of pH (6, 7, 8 and 9), temperature (4, 8 and 16 °C) and osmolalities 100% sea water (1010 mOsm/kg, Control), 75% sea water (774 mOsm/kg, T 1), 50% sea water (488 mOsm/kg, T 2) and distilled water (0 mOsm/ kg, T 3)) on the mo...

La membrana de los espermatozoides juega un papel importante en la capacidad de fertilización. Sin embargo, en peces existen pocas investigaciones que se han centrado en la composición lipídica y estructura de la membrana y el importante papel que ejerce en la interacción espermatozoide-ova. Por lo tanto, el objetivo de este proyecto es estudiar la...

The use of α-tocopherol and ascorbic acid in freezing medium prevents lipoperoxidation and damage by ROS (reactive oxygen species); however, the effects of these antioxidants in salmonid spermatozoa have not been studied. In this work the protective effects of antioxidants on the enzymatic activity and fertilization capacity of frozen Atlantic salm...

In this article we describe basic aspects of the sperm biology of lebranche mullet (Mugil liza) in the wild and in captivity, in particular assessing the effects of salinity (0, 10, 20, 30, 35, 40, 50 and 60 g L-1) and pH (6, 7, 8, 9 and 10) on sperm motility. Our results indicate that the highest percentage of motility was recorded with salinity 3...

Patagonian blenny (Eleginops maclovinus) is the only member of Eleginopidae family. It has been an important resource for Chilean artisanal fishermen communities, however, capture volumes have progressively decreased over last decades likely because overfishing, and concerns for conservation of this species have rised. In this work, mitochondrial D...

Oxidative stress (OS) refers to the imbalance between the generation of reactive oxygen species (ROS) and the ability to scavenge these ROS by endogenous antioxidant systems, where ROS overwhelms the antioxidant capacity. Excessive presence of ROS results in irreversible damage to cell membranes, DNA, and other cellular structures by oxidizing lipi...

Hypobaric hypoxia induces DNA damage in rat testicular cells, the production of defective spermatozoids and decreased sperm count, associated with an increase in oxidative stress. 8-Oxoguanine glycosylase (OGG1) enzymes are main members of the base excision repair (BER) system, a DNA repair mechanism. We determined the expression levels of mitochon...

Short-term storage of semen is a useful strategy for preservation of fish spermatozoa in reproductive management, however, no information is available on Patagonian blenny (Eleginops maclovinus) semen. This study was designed to evaluate the effects of in vitro storage on sperm function parameters in Patagonian blenny. Samples of undiluted (C: cont...

The knowledge of sperm quality in the broodstock males of different ages is a prerequisite to identify the reproductive ability of cultivated fish for the hatchery management. Thus, in this work, we analysed sperm function of the semen stored of broodstock males of rainbow trout (Oncorhychus mykiss) in different reproductive ages (2, 3 and 4 years...

Sperm motility is considered as a key factor allowing determination of semen quality and predicts fertilizing capacity. In many fish species, the spermatozoa are immotile in the testes and seminal plasma, and motility is induced when they are released in the aqueous environment. Initiation and activation of sperm motility are prerequisite processes...

There is an extraordinary diversity of reproductive modes in teleost and this variability is related to the phylogenetic relationships and adaption to very different biotopes. As in all vertebrates, sperm is produced as the end product of the process of spermatogenesis, and regarding teleost the spermatozoa lack an acrosome in almost all species an...

Spermatological research of the Patagonian blennie was carried, specifically biometric parameters, sperm density, sperm count and motility in different activation mediums (815, 716, 590 and 0 mOSm kg À1), at different temperatures (5, 10 and 15°C) and pH levels (5, 7 and 9). The results indicate that Patagonian blennie spermatozoa have a primitive...

Short-term storage of semen is a useful strategy for preservation of fish spermatozoa. However, there is a significantly decrease on sperm function mainly due to oxidative stress. In this way, sodium alginate plays an important role as free radical scavenger compound. Accordingly, the aim of our study was to analyse the effect of a sodium alginate-...

The objective of this study was to determine the effect of freezing on the function in Atlantic salmon Salmo salar spermatozoa. The semen was frozen in Cortland's medium + 1.3M dimethyl sulphoxide + 0.3M glucose + 2% bovine serum albumin (final concentration) in a ratio of 1:3 (semen:cryoprotectant) as the treatment (T) and fresh semen as the contr...

The Zebrafish (Danio Rerio) is a Teleost fish, which offers several practical advan- tages concerning manipulation, maintenance and versatility as well as short life cycle, low cost and physiological similarity with most farmed species. Zebrafish have been used as model for several aquaculture-relevant infectious agents, since the cost of infection...

Semen conservation methods have been extensively studied for fish species over the last 60 years. Cryopreservation techniques can be divided into two types: one with slow cooling rates like traditional freezing and the other with ultrarapid rates as used in vitrification. These protocols increase the time over which semen samples can be used for re...

The development of sperm cryopreservation has enabled transcendental changes to occur in the reproductive biotechnology of both mammals and fish; it has become a basic tool for animal improvement. Nevertheless, these protocols cause damage to cell structure and physiology, altering sperm functioning due to cryoinjuries during freezing and thawing....

Background: Intermittent hypobaric hypoxia (IHH) induces changes in the redox status and structure in rat testis. These effects may be present in people at high altitudes, such as athletes and miners. Polyunsaturated fatty acids (PUFA) can be effective in counteracting these oxidative modifications due to their antioxidants properties. The aim of t...

Despite continuous advances in the knowledge of breast cancer pathophysiology, this type of neoplasia remains a leading cause of cancer-related death in women worldwide. Carcinogenesis takes a progressive course from somatic mutations, alteration of the DNA repair mechanisms, inhibition of growth suppressors, followed by cell proliferation, tissue...

Background Intermittent hypobaric hypoxia (IHH) induces changes in the redox status and structure in rat testis. These effects may be present in people at high altitudes, such as athletes and miners. Polyunsaturated fatty acids (PUFA) can be effective in counteracting these oxidative modifications due to their antioxidants properties. The aim of th...

Sperm cryopreservation has led to transcendental changes in the reproductive biotechnology of both mammals and fish, and is a basic tool for animal improvement. However, these protocols generate damage to cell structure and physiology, altering sperm function as a result of cryoinjuries during freezing and thawing. This review is a compilation of t...

This study was designed to test a vitrification method in Atlantic salmon spermatozoa and determine the capacity of seminal plasma (SP) to protect these cells from cryoinjuries. The vitrification medium consisted of a standard buffer for fish spermatozoa (Cortland®medium) + 10% DMSO + 2% BSA + 0.13 M sucrose + SP at concentrations of 30% (G30), 40%...

The short-term storage of salmonid semen is a viable method for in vitro fertilisation. Previous studies have found that short-term storage affects sperm motility, compromising quality and fertilising capacity. However, the functional characteristics of the spermatozoa of O. mykiss during storage time and its relation to the spawning period are lit...

This work evaluated the incorporation of dimethyl sulphoxide (DMSO) into the medium used for storing rainbow trout semen at 4°C for 13 days. The treatments used were: fresh semen as control (C); semen stored without dilution (T1); semen diluted in saline solution (0.2% KCl and 0.7% NaCl) (T2); T2 + DMSO 1% (T3); T2 + DMSO 2.5% (T4) and T2 + DMSO 5%...

In this article we describe basic aspects of the sperm biology of Merluccius australis, in particular assessing the effects of pH (6, 8 and 10), temperature (4, 10 and 15°C) and osmolality (922mOsm/kg, 822mOsm/kg, 681mOsm/kg and 3mOsm/kg) on sperm motility. Our results indicate the presence of semen with sperm density of 4.6×109sp/ml which contains...

Summary For Salmo salar, there is a lack of information on the morphology of the first blastomeres formed during embryonic development and which could be used as a diagnostic tool for the first stages of development. The purpose of this investigation, therefore, was to characterize morphometrically the first blastomeres of S. salar. From a pool of...

This study was designed to test a vitrification method on spermatozoa of sex-reversed rainbow trout and determine the ability of sucrose, dimethyl sulfoxide (DMSO), bovine serum albumin (BSA) and seminal plasma (SP) to protect these cells from cryoinjuries. The vitrification medium comprised a standard buffer for fish spermatozoa (Cortland®medium)...

Summary There is a lack of information on the morphology of the first blastomeres that could be used as a diagnostic tool for the first stages of embryonic development for Coho salmon. The purpose of this investigation, therefore, was to characterize morphometrically the first blastomeres of Coho salmon (Oncorhynchus kisutch). In total, 660 embryon...

The aims of this investigation were to test a novel technology comprising cryoprotectant-free vitrification of the spermatozoa of rainbow trout and to study the ability of sucrose and components of seminal plasma to protect these cells from cryo-injuries. Spermatozoa were isolated and vitrified using three different media: Group 1: standard buffer...

The aim of the present investigations was to test a novel technology comprising cryoprotectant-free vitrification of the spermatozoa of rainbow trout and to study the ability of sucrose and components of seminal plasma to protect these cells from cryoinjuries. Spermatozoa were isolated and vitrified using five different mediums: Group 1: standard b...