Abstract A total of 381 specimens of the tilapia Oreochromis mossambicus collected monthly from May 2017 to May 2018 in the Laguna de Los Patos, Cumaná, Venezuela, to evaluate reproductive parameters of this non-native species. Significant differences were found in relation to average height and weight between males and females, with the highest values in males. The sex ratio was 1:1.5 (males:females), which deviates significantly from the expected 1:1 ratio. The mean length of sexual maturity (Lm50) was 18.0 cm in females and 20.1 cm in males, reflecting that females mature at smaller sizes than males. The monthly variations of the gonadosomatic index (GSI) and the stages of sexual maturity show two reproductive peaks during the study, in October 2017 and April 2018, coinciding with the rainy and dry seasons in the region respectively. The condition factor (CF) showed significant differences between months, but not between sexes, with an average of 1.87 in females and 1.84 in males. The average absolute fecundity was 921 ± 604.6 eggs per fish, with a relative fecundity of 8.36 ± 3.09 eggs per gram of fish. Differences in oocyte size in mature females confirm that the species can spawn repeatedly over a period, which is considered an important factor for the establishment of tilapia in non-native environments. 38 201 Patos Cumaná Venezuela nonnative non native 11.5 115 1 1.5 5 1:1. malesfemales, malesfemales , (males:females) 11 1: Lm50 Lm (Lm50 180 18 0 18. 20 20. GSI (GSI study respectively CF (CF months sexes 187 87 1.8 184 84 92 6046 604 6 604. fish 836 8 36 8.3 309 3 09 3.0 period environments 11. 15 1. (males:females Lm5 (Lm5 2 9 60 83 8. 30 3. (Lm

Resumo Um total de 381 espécimes da tilápia Oreochromis mossambicus foram coletados mensalmente de maio de 2017 a maio de 2018, na Laguna de Los Patos, Cumaná, Venezuela, para avaliar parâmetros reprodutivos desta espécie não nativa. Foram encontradas diferenças significativas em relação às médias de altura e peso entre machos e fêmeas, sendo os maiores valores no sexo masculino. A razão sexual foi de 1:1,5 (machos:fêmeas), o que se desvia significativamente da proporção esperada de 1:1. O comprimento médio de maturação sexual (Lm50) foi de 18,0 cm nas fêmeas e 20,1 cm nos machos, refletindo que as fêmeas amadurecem em tamanhos menores que os machos. As variações mensais do índice gonadossomático (IGS) e dos estágios de maturidade sexual mostram dois picos reprodutivos durante o estudo, em outubro de 2017 e abril de 2018, coincidindo com as estações chuvosa e seca na região, respectivamente. O fator de condição (FC) apresentou diferenças significativas entre os meses, mas não entre os sexos, com média de 1,87 no sexo feminino e 1,84 no masculino. A fecundidade absoluta média foi de 921 ± 604,6 ovos por peixe, com fecundidade relativa de 8,36 ± 3,09 ovos por grama de peixe. Diferenças no tamanho dos ovócitos em fêmeas maduras confirmam que a espécie pode desovar repetidamente ao longo de um período, o que é considerado um fator importante para o estabelecimento de tilápias em ambientes não nativos. 38 201 2018 Patos Cumaná Venezuela nativa masculino 11,5 115 1 1,5 5 1:1, machosfêmeas, machosfêmeas , (machos:fêmeas) 11. 11 1. 1:1 Lm50 Lm (Lm50 180 18 0 18, 20 20, IGS (IGS estudo região respectivamente FC (FC meses sexos 187 87 1,8 184 84 92 6046 604 6 604, peixe 836 8 36 8,3 309 3 09 3,0 período nativos 11, 15 1, (machos:fêmeas 1: Lm5 (Lm5 2 9 60 83 8, 30 3, (Lm

We characterized the growth and biochemical composition of a Chaetoceros muelleri strain from the Araya Peninsula, Sucre, Venezuela. The microalga was cultured under laboratory conditions (25 ± 1°C, 156 μE m-2 s-1 and 12:12 photoperiod) during 13 days, using two culture methods: batch and semicontinuous culture with a daily renewal rate of 30%. Cell density was determined and cells from each treatment were measured. The protein, lipid, carbohydrate and fatty acid contents were quantified to compare the quality of the Araya strain in both culture systems. Cell density showed little variability in the semicontinuous system during the steady-state phase (1.3 χ 10(6) cells mL-1 on average), but increased significantly in the batch system, reaching 3.5 χ 10(6) cells mL-1. Proteins, lipids and carbohydrates did not show significant variations in the semi-continuous system, with mean values of 21.4 ± 0.8, 18.4 ± 0.8 and 4.1 ± 0.1 pg cells-1, respectively. In the batch system, however, these macromolecules showed greater variability: proteins 3.5-21.1 pg cells-1, lipids 8.5-11.6 pg cells-1 and carbohydrates 4.2-18.1 pg cells-1. Higher levels of saturated (47.5%) and monounsaturated (34.8%) fatty acids were found in the semicontinuous system, whereas the content of polyunsaturated fatty acids (31.4%) was higher in the batch system, in particular of eicosapentaenoic acid (EPA, 20:5 n-3) (16 ± 2% of total fatty acids). Cell size did not vary significantly in the two culture systems and the mean width and length were 5 and 7.5 μm, respectively. The Araya strain of C. muelleri can be used as a food source for cultured larvae, the semicontinuous system providing a more stable nutritional quality.

Se caracterizó bioquímica y poblacionalmente una cepa de Chaetoceros muelleri procedente de la Península de Araya (Venezuela), la cual se cultivó en condiciones de laboratorio (25 ± 1°C, 156 μΕ m-2 s-1 y fotoperiodo 12:12) durante 13 días, bajo sistemas de cultivo discontinuo y semicontinuo con recambios diarios de 30% del volumen. Se evaluó la densidad celular y se determinó el tamaño celular. Se cuantificó el contenido de proteínas, lípidos, carbohidratos y ácidos grasos. La densidad celular tuvo poca variabilidad en el sistema semicontinuo en la fase de estabilización, obteniéndose en promedio 1.3 χ 10(6) cél mL-1, mientras que en el discontinuo, este parámetro incrementó significativamente hasta alcanzar un máximo de 3.5 χ 10(6) cél mL-1. Proteínas, lípidos y carbohidratos no variaron significativamente en los cultivos semicontinuos, alcanzando promedios de 21.4 ± 0.8, 18.4 ± 0.8 y 4.1 ± 0.1 pg cél-1, respectivamente. En el discontinuo, estas macromoléculas presentaron mayor variabilidad, con valores de proteínas entre 3.5 y 21.1 pg cél-1 , lípidos entre 8.5 y 11.6 pg cél-1 y carbohidratos entre 4.2 y 18.1 pg cél-1. Los ácidos grasos saturados y monoinsaturados mostraron valores superiores en los cultivos semicontinuos, con concentraciones de 47.5% y 34.8%, respectivamente. El contenido de ácidos grasos poliinsaturados fue mayor en el sistema discontinuo (31.4%), destacando la presencia del ácido eicosapentaenoico, 20:5 n-3 EPA, con una proporción de 16 ± 2%. El tamaño celular medio de la microalga no varió en los dos sistemas de cultivo, observándose un ancho y largo medios de 5 y 7.5 μm, respectivamente. La cepa de C. muelleri puede suministrarse como alimento de larvas de organismos cultivables, siendo el sistema semicontinuo garantía de una calidad nutricional más estable.

This study aimed: 1) to classify ingredients according to the digestible amino acid (AA) profile; 2) to determine ingredients with AA profile closer to the ideal for broiler chickens; and 3) to compare digestible AA profiles from simulated diets with the ideal protein profile. The digestible AA levels of 30 ingredients were compiled from the literature and presented as percentages of lysine according to the ideal protein concept. Cluster and principal component analyses (exploratory analyses) were used to compose and describe groups of ingredients according to AA profiles. Four ingredient groups were identified by cluster analysis, and the classification of the ingredients within each of these groups was obtained from a principal component analysis, showing 11 classes of ingredients with similar digestible AA profiles. The ingredients with AA profiles closer to the ideal protein were meat and bone meal 45, fish meal 60 and wheat germ meal, all of them constituting Class 1; the ingredients from the other classes gradually diverged from the ideal protein. Soybean meal, which is the main protein source for poultry, showed good AA balance since it was included in Class 3. On the contrary, corn, which is the main energy source in poultry diets, was classified in Class 8. Dietary AA profiles were improved when corn and/or soybean meal were partially or totally replaced in the simulations by ingredients with better AA balance.