DSpace Communidade: Programa de Pós-Graduação em Reprodução Animal na Amazônia

Ontogenia inicial do Tetra Olho-de-Fogo amazônico Moenkhausia oligolepis (Characiformes: characidae)

Thu, 01 Jan 2026 00:00:00 GMT

Título: Ontogenia inicial do Tetra Olho-de-Fogo amazônico Moenkhausia oligolepis (Characiformes: characidae) Autor(es): COIMBRA, Vanessa Conceição Abstract: This study describes, for the first time, the morphophysiological development, allometric growth patterns, and the main early ontogenetic events of Moenkhausia oligolepis, a species of ecological and ornamental importance in the Amazon region. Hatching occurred 16 hours after fertilization under a mean temperature of 25.36 ± 0.64°C and pH of 7.28 ± 1.11. From hatching onward, larvae were sampled at regular intervals (0-6 h post-hatching with collections every 2 h; 6-22 h every 4 h; and subsequently daily) for morphological, morphometric, meristic, and histological analyses. Larval development extended from the yolk-sac stage to post-flexion (0-30 days after hatching – DAH), with a well-defined sequence of events: mouth opening and the onset of exogenous feeding at 3 DAH, observation of cannibalistic behavior at 4 DAH, notochord flexion at 15 DAH (mean SL = 6.33 ± 0.56 mm), and the larva–juvenile transition at 30 DAH with the development of fin rays and the appearance of scales. Allometric analyses revealed positive cephalic growth in relation to standard length (b = 1.389 for HL/SL), indicating prioritization of the development of structures associated with feeding and sensory perception. Structures such as notochord length and pre-anal distance showed growth close to isometry, whereas body depth exhibited negative allometry. Histological analysis demonstrated the progressive differentiation of the digestive tract, with the presence of the buccopharyngeal cavity, esophagus, segmented intestine (anterior, middle, and posterior), and mucous cells at 3 DAH. Cytoplasmic vacuolization in hepatocytes was observed from 23 DAH onward, associated with the presence of digested material in the intestinal lumen. Secondary gill lamellae exhibited evident buds at 4 DAH, and the swim bladder showed division into two chambers by the end of the flexion stage (22 DAH). Gonadal evaluation indicated undifferentiated gonads up to 50 DAH and ovarian differentiation at 60 DAH, characterized by the presence of primary meiotic oocytes; testicular differentiation was not observed during the analyzed period. Based on the observed morphological and ontogenetic characteristics, four larval stages were described: yolk-sac, pre-flexion, flexion, and post-flexion. The results expand the knowledge of the early biology of this species, providing relevant information for taxonomic, ecological, and conservation studies, as well as for improving management strategies and larviculture of native ornamental fishes.

Utilização de Plasma Rico em Plaquetas no Meio de Fertilização in vitro de Oócitos Bovinos.

Thu, 01 Jan 2026 00:00:00 GMT

Título: Utilização de Plasma Rico em Plaquetas no Meio de Fertilização in vitro de Oócitos Bovinos. Autor(es): LIMA, Patrícia de Cássia da Silva Abstract: Culture media represent the physicochemical and utritional support necessary for maintaining the survival and promoting the development of gametes and embryos in vitro. Aiming to replicate a microenvironment closer to in vivo conditions, new formulations and the addition of various substances have been tested. Platelet-rich plasma (PRP) contains serotonin, adhesion molecules, growth factors (FGF, TGFβ, PDGF, IGF, and EGF), as well as cytokines that may positively modulate the fertilization microenvironment and favor embryonic development. Due to its bioactive properties, this study investigated the effect of adding PRP to the fertilization medium on in vitro bovine embryo production. Bovine cumulus–oocyte complexes (COCs) obtained from a local slaughterhouse were fertilized in the presence of 2.5%, 5%, and 10% PRP. The gene expression of OCT4, IFNT, HSP70, SOD2, and GLUT1 was evaluated only in the Control, 2.5%, and 5% groups by RT-PCR, with three replicates consisting of pools of five embryos each, using the 2ΔΔCT method. Cleavage (D2) and blastocyst (D7) rates and gene expression data were analyzed by ANOVA (p<0.05). Regarding cleavage and blastocyst formation rates, differences were observed between the Control (91.9 ± 3.9; 44.6 ± 9.0), 2.5% (87.9 ± 6.4; 39.0 ± 14.1), and 5% (85.8 ± 7.4; 35.1 ± 11.4) groups compared with the 10% group (61.1 ± 9.9; 17.6 ± 4.9). The OCT4 and IFNT genes were more highly expressed in the 5% group, whereas HSP70 showed greater expression in the 2.5% and 5% groups. The SOD2 gene was less expressed in the 2.5% group, while GLUT1 showed lower expression in the 5% group. Therefore, the effect of PRP was dose-dependent, with the 10% concentration exhibiting a detrimental effect on cleavage and blastocyst formation rates. In contrast, 5% PRP during the fertilization process improved the quality of bovine embryos, as evidenced by the higher expression of genes associated with preimplantation embryonic competence.

Exposição aguda à amônia compromete a reprodução e a viabilidade embrionária do lambari Amazônico Astyanax bimaculatus (Linnaeus, 1758).

Thu, 19 Mar 2026 00:00:00 GMT

Título: Exposição aguda à amônia compromete a reprodução e a viabilidade embrionária do lambari Amazônico Astyanax bimaculatus (Linnaeus, 1758). Autor(es): FERREIRA, Evagno Junior da Silva Abstract: This study evaluated the effects of acute ammonia exposure on the reproduction and embryonic and larval viability of the Amazonian tetra species (Astyanax bimaculatus). Adult breeders were exposed to a sublethal concentration of ammonia (NH₄Cl, 180 mg/L) for 4 hours before artificial reproduction. The results showed a significant reduction in hatching rates (82.3 ± 0.577 (41,2%) vs. 129 ± 1.73 (64,5%) in the control) and an acceleration in hatching time (1005 ± 2.58 vs. 1026 ± 3.65 minutes). Gonadal histology revealed alterations in gametogenesis, with exposed females exhibiting fewer vitellogenic oocytes and a higher number of post-ovulatory follicular complexes, while males presented a larger number of spermatocytes and interstitial tissue, and a reduction in spermatozoa. In both cases, indicating early release of gametes. Morphometric analysis of larvae from exposed breeders indicated delayed growth at 10 days post-hatching, although no morphological abnormalities were observed. These findings demonstrate the impact of ammonia on reproductive success and larval development in fish, emphasizing the importance of strict water quality management in aquaculture to mitigate such effects.

Aspectos reprodutivos de uma população de guará (Eudocimus ruber) sob cuidados humanos em baixa latitude.

Tue, 03 Jun 2025 00:00:00 GMT

Título: Aspectos reprodutivos de uma população de guará (Eudocimus ruber) sob cuidados humanos em baixa latitude. Autor(es): GONZÁLEZ GONZÁLEZ, Camilo Andrés Abstract: This thesis was divided into two chapters. In the first chapter, the objective was to describe the embryonic development of semi-altricial scarlet ibis (Eudocimus ruber) while identifying critical landmarks for diagnostic and age determination purposes, supporting both artificial incubation and field research on the species. We used eggs collected from a captive population in northern Brazil. A total of 50 embryos were analyzed from day 0 to day 18, focusing on external morphological traits observable through macroscopic examination. Key diagnostic features included the sequential formation of the beak, eyes, neck, feathers, and embryonic annexes. We compared the development of the semi-altricial scarlet ibis with reference descriptions of precocial and altricial species to evaluate the suitability of comparisons between different postnatal growth patterns. The semi-altricial scarlet ibis exhibited heterochronic variations of up to four days in critical developmental landmarks compared to precocial species with similar incubation periods. These findings suggest that developmental timelines. established for precocial species may not be reliable for accurately staging altricial and semi-altricial embryos. Interestingly, the median timing of significant developmental events in the scarlet ibis aligned more closely with those of other altricial species. The daily embryonic milestones described herein provide a valuable reference for scarlet ibis captive breeding programs and contribute to broader conservation efforts for other Threskiornithidae family members or species within the Pelecaniformes order, addressing the limited research on semi-altricial avian development. In the second chapter, we aimed to describe the breeding performance of a captive population of scarlet ibis over a three-year period (2022, 2023, and 2024). We focused on various factors, including the onset and conclusion of the breeding season, couple formation, enclosure density, and laying timing. We conducted statistical analyses to assess the impact of breeder-related factors (such as age and laying timing), egg characteristics (including weight and shape), and incubation parameters (such as egg weight loss) on key zootechnical variables commonly used in poultry production, including laying rate, fertility, and hatchability. Our goal was to establish a breeder profile that could inform mate selection. The onset of the breeding season varied between July and August over the three years, while its conclusion ranged from November to January. Both males and females began forming breeding pairs as early as two years old, with the oldest pairing ages being 20 years for males and 12 years for females. 82,6 ± 4.9% of pairs were monogamous throughout the season. Higher enclosure densities appeared to improve laying rates and encourage earlier laying, while a 1:1 male-to-female ratio facilitated effective pair formation with minimal aggression. Additionally, increased female age correlated with a higher laying rate (p < 0.05). Egg withdrawal stimulated the replacement of eggs in females, resulting in an average of 7.6 ± 2.7 new eggs. The advancement of the laying season significantly influenced initial egg weight (p < 0.01). The median daily weight loss during incubation was 0.74% (tau = 0.5), while the mean weight loss on day 21 was 19 ± 2%. The findings from this study are invaluable for planning efficient breeding programs for the scarlet ibis and potentially for other members of the Threskiornithidae family.