During fin regeneration, a blastema, a group of de-differentiated cells, forms underneath the wound epidermis. As regeneration proceeds, cells leave the proximal blastema and enter the differentiation zone. Adjacent to the differentiation zone, a subset of cells in the basal epidermal layer (BEL) express sonic hedgehog a (shha). Cells that come in contact with BEL differentiate into osteoblasts and joint cells, enabling the formation of bone segments at the end of each fin ray. Generally, fin regeneration occurs similarly in males and females. However, breeding tubercles (BT), keratinized epidermal structures on the male pectoral fin, result in regenerative differences when compared to females. In this thesis, three aspects of zebrafish fin regeneration were studied: 1) Cell lineage tracing of shha-expressing cells in the caudal fin regenerate; 2) The differentiation of joint cells and osteoblasts in the caudal fin regenerate; 3) Regeneration of pectoral fin BTs. Studies on caudal fin regenerates suggest osteoblasts and joint cells originate from a common cell lineage, but are committed to different cell fates. Joint cells follow a genetic pathway in which evx1 occurs downstream or parallel to hoxa13a and upstream of pthrp1. In the absence of Evx1, presumptive joint cells are committed to an osteoblast cell fate. Furthermore, joint cells do not regenerate following laser cell ablation, suggesting joint cell differentiation occurs only at specific intervals during osteoblast regeneration. Collectively, these results suggest a mechanism for joint cell differentiation during caudal fin regeneration. Studies on pectoral fins indicate androgens induce and estrogens inhibit BT formation. BT regeneration in males and androgen-treated females follows the initiation of revascularization, but occurs concomitantly with a novel second wave of angiogenesis. The inhibition of angiogenesis in androgen-treated females prevents BT formation. Altogether, these results suggest the growth and regeneration of BTs requires a v hormonal stimulus and the presence of an additional blood vessel network naturally found in males. In conclusion, these studies have increased the overall knowledge of key aspects of zebrafish fin regeneration. A gain in understanding zebrafish regeneration provides a basis in which treatments can be developed to induce regeneration in species with limited regenerative capabilities.

Thèse d'exercice : Médecine. Rhumatologie : Nantes : 2008. / Bibliogr.

No description available.

Thesis advisor: Sarah McMenamin / Pectoral fins are evolutionarily homologous to tetrapod limbs and can serve as useful models for studying the genetic and hormonal factors regulating appendage development. To test the roles of thyroid hormone (TH) in the development of these appendages, we examined the morphogenesis of zebrafish pectoral fins under euthyroid (EuTH) or hypothyroid (hypoTH) conditions. TH plays an important role in modulating the development of the pectoral fin endoskeleton, as well as the proximo-distal patterning of the fin rays. Additionally, in HypoTH fish, shh was expressed in the same domains, but at ~50% of WT expression levels. Nuclear TH acts by binding to dual-action receptors, including Thrab, which represses or activates expression depending on interaction with the TH ligand. When Thrab was absent in HypoTH fish, we found that many elements of the HypoTH phenotype were rescued, suggesting TH relieves Thrab- mediated repression. We also found that TH modulates the development of the musculature surrounding the pectoral fin. Lastly, we generated CRISPR-Mediated knockouts of dio1 and dio3b, to learn how the deiodination of TH may be affecting the development of the pectoral fin. / Thesis (BS) — Boston College, 2023. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Departmental Honors. / Discipline: Biology.

Thèse ou mémoire avec insertion d'articles / Le but de cette étude était d'évaluer et de comparer l'état de la qualité de la viande de poitrine des deux souches de poulets de chair à rendement standard les plus utilisées sur le marché mondial : Cobb 500 et Ross 308. Pour ce faire, des poussins des deux sexes des deux souches ont été placés dans un design en blocs complets randomisés (4 groupes x 4 répétitions en 4 blocs) et nourris d'un régime standard de démarrage, de croissance et de finition de 1 à 35 jours. À 35 jours, les oiseaux (n = 40/souche/sexe) ont été abattus et leur rendement et la qualité de la viande de poitrine ont été évalués. L'interaction souche-sexe n'était pas significative pour la plupart des caractères analysés. Les oiseaux de la souche Cobb 500 avaient un poids corporel plus élevé (*P* < 0,001), un rendement en viande de poitrine plus élevé (*P* = 0,02) et un rendement en cuisse moins important (*P* < 0,001) que les Ross 308. Ils présentaient également un score plus élevé (*P* = 0,04) de la myopathie de durcissement de la poitrine et des pertes d'eau plus importantes par exsudation (*P* = 0,01) et après cuisson (*P* = 0,01). Un modèle de glycolyse *in vitro* a révélé que la chute post-mortem du pH du muscle *Pectoralis major* était influencée par l'interaction entre la souche et l'âge (*P* < 0,001). À 14 jours, le pH initial était plus élevé (*P* < 0,05) chez Cobb 500, mais à 33 jours, il était similaire dans les deux souches. Aux deux âges et pour les deux souches, le pH ultime de ce muscle a été atteint à3 heures post-mortem. En conclusion, le développement musculaire est négativement corrélé à la qualité de la viande. Par conséquent, le choix de combinaison de souches et de sexe pour la production de poulets de chair nécessite un compromis entre le rendement et la qualité de la viande. / The purpose of this study was to evaluate and compare the state of breast meat quality in the two most used standard-yielding broiler chicken strains on today's market: Cobb 500 and Ross 308. To achieve this, chicks from both sexes of both strains were placed in a randomized complete block design (4 groups × 4 replicates in 4 blocks) and fed a standard starter, grower, and finisher diet from 1 to 35 d. At 35 d, birds (n = 40/strain/sex) were processed, and their yield and breast meat quality were evaluated. The strain-by-sex interaction was not significant for most analyzed traits. Birds from the Cobb 500 strain had higher body weight (*P* < 0.001), greater breast meat yield (*P* = 0.02), and lower leg meat yield (*P* < 0.001) than Ross 308 birds. They also exhibited higher wooden breast score (*P* = 0.04) and greater dri*P* (*P* = 0.01) and cooking (*P* = 0.01) losses. An in vitro glycolysis model revealed that post-mortem decline in the pH of the *Pectoralis major* muscle was influenced by the interaction between strain and age (*P* < 0.001). At 14 d, the initial pH was higher (*P* < 0.05) in Cobb 500, but at 33 d it was similar in both strains. At both ages and for both strains, the ultimate pH in this muscle was reached at 3 h post-mortem. In conclusion, muscle growth and development are negatively associated with meat quality. Thus, the choice of strain and sex combinations for broiler production requires a compromise between meat yield and quality.

Channel catfish have pectoral spines that lock to defend against gape-limited predators such as largemouth bass. Previous work indicated that spines increase survival of channel catfish exposed to bass but did not determine whether bass avoid catfish if less dangerous species are available. We presented bass with channel catfish and two alternatives, bluegill and goldfish, and compared order of ingestion, ingestion time, percent of successful strikes, and time spent chasing each prey species. We also presented the three species in a jar study that standardized position in the water column as well as in a net-pen study. The order of ingestion was suggestive of a preference for goldfish, then bluegill and finally channel catfish. Handling time was greater for channel catfish, less for bluegill, and the least for goldfish. Fewer catfish were eaten when other prey were available. Bass appear to avoid channel catfish if alternative prey is available.

A importância econômica da carne de aves conduziu extensivos esforços de seleção genética para aumentar o rendimento de peito de frangos de corte comerciais proporcionando músculos formados com o dobro de fibras musculares e com maior diâmetro. Esse aumento causou a incidências de alterações musculares peitorais denominadas de White Striping e Wooden Breast, conhecida respectivamente como estrias brancas e peito madeira. Foram utilizados 1.755 pintos de 3 linhagens (Cobb, Ross e Hubbard) distribuídos em delineamento inteiramente casualizado em arranjo fatorial 3X5 (três linhagens, cinco estratégias nutricionais) com nove repetições por tratamento, distribuídas em 135 boxes e densidade de 13 aves/m². Foram abatidas 1 ave por repetição aos 35, 42, 49 e 56 dias para as análises de desempenho, rendimento de carcaça e cortes, miopatias peitorais e composição nutricional do peito. As estratégias nutricionais (EN) foram: EN1 - desempenho regular, 500 FTU de fitase; EN2 - desempenho superior, 500 FTU de fitase; EN3 - desempenho superior, 1500 FTU; EN4 - desempenho superior, 500 FTU, complexo antioxidante; EN5 - desempenho superior, 1500 FTU, complexo antioxidante. Entre as linhagens, Ross predominou com o maior consumo de ração com 21, 49 e 56 dias e maior peso médio em todas as idades. A linhagem Hubbard que prevaleceu com a menor conversão alimentar aos 49 e 56 dias de idade. Para rendimento de carcaça Cobb e Ross foram superiores ao Hubbard com 35 dias e predominaram maior rendimento de peito entre as idades de abate. Hubbard obteve maior rendimento de pernas em todas as idades. Para consumo de ração, peso médio e conversão alimentar por EN, o consumo de ração só apresentou diferença significativa entre as EN nas fases iniciais (8-21 dias) e finais (50-56 dias). Quando observado o peso médio, a EN 5 teve o maior peso em todas as idades. O menor peso foi para as aves da EN 1 em todas as idades. Na análise de conversão percebe-se que a EN 1 teve a maior conversão nas fases: inicial (8-21 dias), crescimento (22-49 dias) e final (50-56 dias). EN 5 obteve a menor conversão alimentar na fase inicial e final. Não houve diferença significativa para incidência de White Striping em todas as idades entre linhagens. Para Wooden Breast (WB), houve diferença significativa entre as linhagens com 42, 49 e 56 dias de idade, onde Cobb prevaleceu com maior incidência nessas idades. Ross obteve junto ao Cobb as maiores incidências com 49 e 56 dias. Não houve diferença significativa entre White Striping e Wooden Breast entre as estratégias nutricionais. Para composição química do peito das aves entre as linhagens, observa-se que só houve diferença significativa para extra etéreo (EE) com 49 dias de idade, onde Cobb e Ross tiveram o maior percentual. Entre as estratégias nutricionais não houve diferença significativa para composição nutricional do peito. Há diferença significativa entre Cobb, Ross e Hubbard para desempenho e rendimento, o que afetam a incidência das miopatias peitorais. No entanto, entre as estratégias nutricionais não observou diferença significativa para incidências de White Striping e Wooden Breast. / The economic importance of poultry meat led extensive genetic selection efforts to increase breastfeeding of commercial broilers by providing muscles formed with twice the muscle fibers and with larger diameter. This increase caused incidences of pectoral muscle changes called White Striping and Wooden Breast, known respectively as white striations and chest wood. A total of 1,755 chicks (Cobb, Ross and Hubbard) were distributed in a completely randomized design in a 3X5 factorial arrangement (three lines, five nutritional strategies) with nine replicates per treatment, distributed in 135 boxes and density of 13 birds / m². One bird per replicate was slaughtered at 35, 42, 49 and 56 days for analyzes of performance, carcass yield and cuts, pectoral myopathies and nutritional composition of the breast. The nutritional strategies (EN) were: EN1 - regular performance, 500 FTU of phytase; EN2 - superior performance, 500 FTU of phytase; EN3 - superior performance, 1500 FTU; EN4 - superior performance, 500 FTU, antioxidant complex; EN5 - superior performance, 1500 FTU, antioxidant complex. Among the lineages, Ross predominated with the highest feed intake at 21, 49 and 56 days and highest mean weight at all ages. The Hubbard strain prevailed with the lowest feed conversion at 49 and 56 days of age. For carcass yield Cobb and Ross were superior to Hubbard with 35 days and had a higher breast yield between the slaughter ages. Hubbard obtained higher leg yield at all ages. For feed intake, mean weight and feed conversion by EN, feed intake only showed a significant difference between the early (8-21 days) and the late (50-56 days). When the average weight was observed, EN 5 had the highest weight in all ages. The lowest weight was for birds of EN 1 at all ages. In the conversion analysis, it was observed that EN 1 had the highest conversion in the phases: initial (8-21 days), growth (22-49 days) and final (50-56 days). EN 5 obtained the lowest feed conversion in the initial and final phases. There was no significant difference in the incidence of White Striping at all ages between strains. For Wooden Breast (WB), there was a significant difference between the 42, 49 and 56 days old strains, where Cobb prevailed with higher incidence at these ages. Ross obtained the highest incidences with Cobb at 49 and 56 days. There was no significant difference between White Striping and Wooden Breast between nutritional strategies. It was observed that there was only a significant difference for fat at 49 days of age, where Cobb and Ross had the highest percentage. Among nutritional strategies there was no significant difference in the nutritional composition of the breast. There is a significant difference between Cobb, Ross and Hubbard for performance and yield, which affect the incidence of pectoral myopathies. However, among the nutritional strategies did not observe significant difference for incidences of White Striping and Wooden Breast.

Polypterus is an extant fish that is used as a model to understand the fin-to-limb evolutionary transition. Polypterus exhibits muscle phenotypes relevant to this transition. In particular, plastic changes in bone and muscle in Polypterus have been shown in response to spending time in a terrestrial environment. Muscle fiber changes are usually associated with changes in the performance demand placed on those muscles. We hypothesize that muscle fibers are recruited differently between aquatic and terrestrial environments to explain the change in fiber type. How pectoral fin muscle activity changes between swimming and walking is mostly unknown. Hence, this study utilizes electromyography (EMG) and high-speed videography to understand how the muscle activity pattern and function of all four pectoral fin muscle groups change during swimming and walking in aquatically raised fish. In this experiment, aquatically raised fish were placed in water and on land to observe changes in fin muscle function between behaviours. This study aims to understand how the instantaneous changes in the behaviour of the fish, particularly in the pectoral fin, could explain the muscle plasticity found in previous research. This study showed that fish adduct their pectoral fins much faster with increased muscle effort during walking compared to swimming. The adductor muscle also had the biggest change in function, activating for the majority of the fin-stroke cycle and therefore undergoing eccentric contraction. The increase in muscle effort seen in this study is consistent with the muscle fiber transition seen in fish that spend long periods on land, and the dramatic change of EMG magnitudes found in the adductor muscle may explain muscle damage previously found following acute walking.

Polypterus senegalus, an extant member of the ray-finned fishes, can both swim in water and walk overland. Both environments impose different locomotor requirements on Polypterus fins. In an aquatic environment, forward propulsion is largely generated through oscillations of the pectoral fins working in sync with each other. On land, the pectoral fins are engaged in a contralateral gait, and are involved in lifting the body off the ground while simultaneously balancing the body. Polypterus have been shown to undergo behavioural, anatomical, and physiological changes during both short- and long-term exposure to land. Differences in force environments and locomotor behaviour between aquatic and terrestrial environments are hypothesized to be the cause of these plastic changes observed in the musculoskeletal tissues of Polypterus. Despite these observable changes, it is unclear exactly how the pectoral fins are experiencing ground reaction forces (GRF) during terrestrial locomotion. By measuring and quantifying force production during walking in Polypterus, this thesis provides a first look at the relationship between GRFs produced and experienced during walking and the pectoral fins of the amphibious fish, Polypterus. The kinematics of the pectoral fins and fore body were analyzed during terrestrial locomotion, and strategic points across both pectoral fins and body were digitized. Kinematics were compared with GRFs in the thrust (X), stabilizing (Y) and lifting (Z) planes to understand how impact forces travel through the fin tissues. Further analysis, using inverse dynamics, is required to determine how these impact forces travel through the musculature of the pectoral fins, perhaps providing potential hypotheses as to the effects of GRFs and their role in not only how terrestrial locomotion affects the behavioural, anatomical, and physiological plasticity observed in Polypterus, but also the limbs of tetrapods during the evolutionary transition from aquatic to terrestrial environments.

No description available.