Secondary sexual dimorphism and ontogenetic shifts in habitat use by the lesser guitarfish Zapteryx brevirostris.

Sexual dimorphisms are generated by divergent processes, such as natural or sexual selection and niche convergence. Males and females of the lesser guitarfish, Zapteryx brevirostris, present morphological differences in their discs, and the relationships with the species biology and ecology were unrecognized. Analysing the morphometry of 201 specimens and the influence of bottom features on the frequencies of 188 specimens among life stages and sexes, we found strong evidence that gonadal maturation leads to dimorphisms on discs, validating a concavity on male pectoral fins as a secondary sexual dimorphism and rejecting the hypothesis that such dimorphisms were related to ecological pressures. The principal component analysis (PCA) and permutational MANOVA (PERMANOVA) analyses revealed that males and females shared similar body aspects until they reached maturity, mainly due to lower variations in WD, WR, LD, DPRO, and LSC at younger life stages. The relationships of these variables with LT corroborate the former results, showing a changing point around LT > 30 cm where females started to attain larger measurements than males. Moreover, we revealed ontogenetic shifts, with adults from both sexes exploring different habitats than juveniles and subadults. Differences in frequencies of each life stage were best explained by organic matter (OM) with the adults exploring bottom habitats of higher concentrations of OM than juveniles and subadults, strengthening the assumption that body differences between sexes are not related to ecological pressures. These results bring not only new insights about the possible advantages that those morphometric differences provide to males while mating but also information about the abiotic influences on species distribution, which, along with knowledge of local oceanographic dynamics and benthic community patterns, would inform actions for species conservation.

Body and testicular development and serum testosterone concentrations in Brahman males / Desenvolvimento corpóreo, testicular e concentrações séricas de testosterona em machos Brahman

The present study had the objective of evaluating the physical and testicular development, and the serum testosterone concentration of 8 to 18 months old male Brahman cattle on grazing weight gaining performance tests. Bovine cattle (n=40), aged 259.76 ± 26.15 days and weighing 239.71 ± 33,94kg had the following characteristics evaluated every 56 days, corresponding to 8, 10, 12, 14, 16, and 18 months of age (six different data collections): body weight (BW), scrotal circumference (SC), girth (G), height at the withers (WH), body length (BL), body mass index (BMI), right and left testicular length (RTL and LTL, respectively), right and left testicular height (RTH and LTH, respectively), average daily weight gain (ADG), testicular volume (TV), and serum testosterone (ST).Analysis of variance and Tukey"s test at 5% probability were used. Correlations between variables were assessed using Pearson"s method at 5% confidence. There was significant difference (P < 0.05) from 12 months of age onwards for ADG and ST. There were differences (P < 0.05) for: BW, SC, G, WH, BL, BMI, RTL, LTL, RTH,and TV from 14 months of age. There was a positive correlation between: ST x G (r=0.38; P < 0.01); ST x WH (r=0.38; P < 0.01); ST xRTH (r=0.23; P < 0.05); ST x LTH (r=0.21; P < 0.01); ST x TV (r=0.22; P < 0.008); TV x weight (r=0.70; P < 0.01); TV x SC (r=0.90; P < 0.01); and TV x BMI (r=0.93; P < 0.01). Arapid increase in serum testosterone concentration occurred between 12 and 14 months of age, followedby rapid body and testicular growth. An elevation in testosterone levels is an indirect indicator that anacceleration inphysical and testicular growth is approaching. It is recommended to calculate both BMIand TV to follow cattle growth due to the high correlation between these variables.(AU)

Objetivou-se estudar o desenvolvimento corpóreo, testicular e a concentração sérica de testosterona dos 8 aos 18 meses de idade de machos Brahman em prova de ganho de peso à pasto. Os bovinos (n=40) com idade de 259,76±26,15 dias e peso de 239,71±33,94kg, foram avaliados a cada 56 dias, em seis momentos, respectivamente, aos 8, 10, 12, 14, 16 e 18 meses de idade para: peso corpóreo (PC), circunferência escrotal (CE), perímetro torácico (PT), altura de cernelha (HC), comprimento corporal (CC), índice de massa corpórea (IMC), comprimento testicular direito (CTD) e esquerdo (CTE), altura testicular direita (HTD) e esquerda (HTE), ganho médio diário de peso corpóreo (GMD), volume testicular (VT) e concentração sérica de testosterona (TES).Utilizou-se a análise de variância, seguida por Tukey a 5%. Para as correlações entre variáveis se empregou o método de Pearson a 5%. Houve diferença (P < 0,05) dos 12 meses de idade em diante para GMD e TES. Houve diferenças (P < 0,05) para: PC, CE, PT, HC, CC, IMC, CTD, CTE, HTD e VT à partir de 14 meses de idade. Houve correlações positivas entre: TES x PT (r = 0,38; P < 0,01); TES x HC (r = 0,38; P 0,01); TES x HTD (r = 0,23; P < 0,05); TES x HTE (r = 0,21; P < 0,01); TES x VT (r = 0,22; P < 0,008) e do VT x peso (r = 0,70; P < 0,01); VT x CE (r = 0,90; P < 0,01) e VT x IMC (r = 0,93; P < 0,01). A elevação rápida da concentração sérica detestosterona ocorreu entre 12 e 14 meses de idade. Houve rápido crescimento corpóreo e dos testículosapós a elevação significativa de testosterona. A elevação da testosterona, de forma indireta, indicaa proximidade da aceleração do crescimento corpóreo e testicular. Recomenda-se calcular o índicede massa corpórea e o volume testicular para acompanhar o crescimento dos bovinos, devido à altacorrelação entre essas variáveis.(AU)

Body and testicular development and serum testosterone concentrations in Brahman males / Desenvolvimento corpóreo, testicular e concentrações séricas de testosterona em machos Brahman

The present study had the objective of evaluating the physical and testicular development, and the serum testosterone concentration of 8 to 18 months old male Brahman cattle on grazing weight gaining performance tests. Bovine cattle (n=40), aged 259.76 ± 26.15 days and weighing 239.71 ± 33,94kg had the following characteristics evaluated every 56 days, corresponding to 8, 10, 12, 14, 16, and 18 months of age (six different data collections): body weight (BW), scrotal circumference (SC), girth (G), height at the withers (WH), body length (BL), body mass index (BMI), right and left testicular length (RTL and LTL, respectively), right and left testicular height (RTH and LTH, respectively), average daily weight gain (ADG), testicular volume (TV), and serum testosterone (ST).Analysis of variance and Tukey"s test at 5% probability were used. Correlations between variables were assessed using Pearson"s method at 5% confidence. There was significant difference (P < 0.05) from 12 months of age onwards for ADG and ST. There were differences (P < 0.05) for: BW, SC, G, WH, BL, BMI, RTL, LTL, RTH,and TV from 14 months of age. There was a positive correlation between: ST x G (r=0.38; P < 0.01); ST x WH (r=0.38; P < 0.01); ST xRTH (r=0.23; P < 0.05); ST x LTH (r=0.21; P < 0.01); ST x TV (r=0.22; P < 0.008); TV x weight (r=0.70; P < 0.01); TV x SC (r=0.90; P < 0.01); and TV x BMI (r=0.93; P < 0.01). Arapid increase in serum testosterone concentration occurred between 12 and 14 months of age, followedby rapid body and testicular growth. An elevation in testosterone levels is an indirect indicator that anacceleration inphysical and testicular growth is approaching. It is recommended to calculate both BMIand TV to follow cattle growth due to the high correlation between these variables.

Objetivou-se estudar o desenvolvimento corpóreo, testicular e a concentração sérica de testosterona dos 8 aos 18 meses de idade de machos Brahman em prova de ganho de peso à pasto. Os bovinos (n=40) com idade de 259,76±26,15 dias e peso de 239,71±33,94kg, foram avaliados a cada 56 dias, em seis momentos, respectivamente, aos 8, 10, 12, 14, 16 e 18 meses de idade para: peso corpóreo (PC), circunferência escrotal (CE), perímetro torácico (PT), altura de cernelha (HC), comprimento corporal (CC), índice de massa corpórea (IMC), comprimento testicular direito (CTD) e esquerdo (CTE), altura testicular direita (HTD) e esquerda (HTE), ganho médio diário de peso corpóreo (GMD), volume testicular (VT) e concentração sérica de testosterona (TES).Utilizou-se a análise de variância, seguida por Tukey a 5%. Para as correlações entre variáveis se empregou o método de Pearson a 5%. Houve diferença (P < 0,05) dos 12 meses de idade em diante para GMD e TES. Houve diferenças (P < 0,05) para: PC, CE, PT, HC, CC, IMC, CTD, CTE, HTD e VT à partir de 14 meses de idade. Houve correlações positivas entre: TES x PT (r = 0,38; P < 0,01); TES x HC (r = 0,38; P 0,01); TES x HTD (r = 0,23; P < 0,05); TES x HTE (r = 0,21; P < 0,01); TES x VT (r = 0,22; P < 0,008) e do VT x peso (r = 0,70; P < 0,01); VT x CE (r = 0,90; P < 0,01) e VT x IMC (r = 0,93; P < 0,01). A elevação rápida da concentração sérica detestosterona ocorreu entre 12 e 14 meses de idade. Houve rápido crescimento corpóreo e dos testículosapós a elevação significativa de testosterona. A elevação da testosterona, de forma indireta, indicaa proximidade da aceleração do crescimento corpóreo e testicular. Recomenda-se calcular o índicede massa corpórea e o volume testicular para acompanhar o crescimento dos bovinos, devido à altacorrelação entre essas variáveis.

Fatores que afetam o desempenho de cordeiros Santa Inês puros e cruzados do nascimento ao desmame

The objective of this study was to evaluate the environmental effects (age of dam, type of birth, sex of the lamb and year of birth) and genetic groups on the weight and morphometric measurements of lamb at birth and at weaning; test regressions for predicting weight of lambs by the measurements and describe the type of growth of the measures. Lambs of young ewes (2 teeth) had lower average for all characteristics except height at weaning. The average birth weight ranged from 3.34 ± 0.14kg in the offspring of two teeth ewes to 3.94 ± 0.09kg in the lambs of eight teeth ewes, and for weaning weight ranged from 12.19 ± 0.72kg in the offspring of two teeth ewes, and 14.79 ± 0.62 in the lambs of six teeth ewes. The single birth lambs had highter averages than the twins. Means for birth weight ranged from 3.24 ± 0.11kg to 4.08 ± 0.06kg and for weaning weight from 11.18 ± 0.59kg to 15.81 ± 0.35kg, the averages were lower for twins and greater for single lambs. The genetic group affected the weight and the length and height at birth, where purebred Santa Inês lambs presented greater averages than ½ Santa Inês lambs. The year of birth influenced all traits. All correlations between weights and measures were significant. It is possible to predict the weight on the basis of measures.

Objetivou-se avaliar os efeitos ambientais (idade da mãe ao parto, tipo de nascimento, sexo do cordeiro e ano de nascimento) e os grupos genéticos sobre o peso e medidas morfométricas de cordeiros, ao nascimento e ao desmame; testar regressões para predizer peso por meio das medidas e descrever o tipo de crescimento das medidas. Os filhos de ovelhas mais jovens (dois dentes) apresentaram médias menores para todas as características, exceto altura ao desmame. As médias de peso ao nascimento variaram de 3,34 ± 0,14kg nos filhos de ovelhas de dois dentes a 3,94 ± 0,09kg nos filhos de ovelhas de oito dentes, e as de peso ao desmame variaram de 12,19 ± 0,72kg nos filhos de ovelhas de dois dentes a 14,79 ± 0,62 nos filhos de ovelhas de seis dentes. Os cordeiros nascidos de partos simples apresentaram maiores médias que os gêmeos. As médias de peso ao nascer foram de 3,24 ± 0,11kg a 4,08 ± 0,06kg e para peso ao desmame foram de 11,18 ± 0,59kg a 15,81 ± 0,35kg, as médias menores foram dos cordeiros gêmeos e as maiores dos cordeiros simples. O grupo genético influenciou o peso, o comprimento e a altura ao nascimento, os Santa Inês puros apresentaram médias maiores que os ½ Santa Inês. O ano de nascimento influenciou todas as características. Todas as correlações entre pesos e medidas foram significativas, e assim foi possível prever o peso em função das medidas.