Supplement levels and functional oils to replace virginiamycin for young bulls during early dry season on grasslands and finishing phase in feedlot systems

Aim of study: To assess the effects of replacing virginiamycin (VM) by functional oils (FO) from castor beans and cashew nut on beef cattle system during the early dry season (Experiment I) and during the finishing phase were evaluated the historical effect, keeping the treatments and methods intact (Experiment II).Area of study: These experiments were conducted at the Forage Crops and Grasslands section of São Paulo State University, “Julio de Mesquita Filho” (Unesp–Jaboticabal, São Paulo, Brazil).Material and methods: Two supplementation levels combined with two additives (four treatments in total) were evaluated: LSVM, low supplementation (0.3% body weight [BW]) with VM; LSFO, low supplementation (0.3% BW) with FO, HSVM, high supplementation (0.6% BW) with VM, and HSFO, high supplementation (0.6% BW) with FO. In both experiments, the experimental design was completely randomized with a 2 × 2 factorial arrangement (supplementation levels × additives).Main results: In Exp. I, the additive effect of VM provided greater average daily gain (ADG, p=0.02), higher supplementation level resulted in higher ADG (p=0.04) and the greatest crude protein apparent digestibility (p=0.002). However, no effects were observed between supplementation levels, additives, and interactions (p≥0.11) on voluntary intake and ruminal parameters. In Exp. II, LSVM treatment resulted in lower dry matter intake (p=0.04). Animals maintained on LSFO during the early dry season exhibited lower carcass yield (p=0.004).Research highlights: FO can be used to replace VM in beef cattle diet during the finishing phase in the feedlot without altering animal performance

Two new species of Odontostilbe historically hidden under O. microcephala (Characiformes: Cheirodontinae)

Specimens historically identified as Odontostilbe microcephala from the upper rio Paraná and Andean piedmont tributaries of the río Paraguay are reviewed and split in three species. We found that the distribution of O. microcephala is restricted to the Andean slope of the río Paraguay basin. The species is distinguished from congeners with subterminal mouth by the elongate body, usually 10-12 gill rakers on upper branch and smaller horizontal orbital diameter (24.6-32.8 % HL, mean 28.7%). Specimens from upper rio Paraná constitute two new species, diagnosed from other Cheirodontinae by the presence of mesopterygoid teeth, grouped on median portion and forming a continuous row. The new species are distinguished from each other by having premaxillary teeth with five cusps vs. nine cusps and by the number of lamellae in left and right sides of central median raphe of olfactory rosette with 20-21 vs. 11-12.Espécimes historicamente identificados com Odontostilbe microcephala do rio Paraná e tributários do río Paraguay, foram revisados e separados em três espécies. A distribuição de O. microcephala é restrita ao sopé andino da bacia do río Paraguay. A espécie é distinta das congêneres com boca subterminal pela forma alongada, geralmente 10-12 rastros branquiais no ramo superior e menor diâmetro horizontal da órbita (24,6-32,8 % CC, média 28,7%). Espécimes do alto rio Paraná constituem duas espécies novas diagnosticadas de outros Cheirodontinae pela presença de dentes no mesopterigoide, agrupados em sua porção média e formando uma fileira continua. As novas espécies distinguem-se por ter dentes premaxilares com cinco cúspides vs. nove cúspides e pelo número de lamelas nos lados esquerdo e direito da rafe central da roseta olfativa com 20-21 vs. 11-12

Evidence of niche partitioning under ontogenetic influences among three morphologically similar siluriformes in small subtropical streams

Ontogenetic influences in patterns of niche breadth and feeding overlap were investigated in three species of Siluriformes (Heptapterus sp., Rhamdia quelen and Trichomycterus poikilos) aiming at understanding the species coexistence. Samplings were conducted bimonthly by electrofishing technique from June/2012 to June/2013 in ten streams of the northwestern state of Rio Grande do Sul, Brazil. The stomach contents of 1,948 individuals were analyzed by volumetric method, with 59 food items identified. In general Heptapterus sp. consumed a high proportion of Aegla sp., terrestrial plant remains and Megaloptera; R. quelen consumed fish, and Oligochaeta, followed by Aegla sp.; while the diet of T. poikilos was based on Simuliidae, Ephemeroptera and Trichoptera. Specie segregation was observed in the NMDS. Through PERMANOVA analysis feeding differences among species, and between a combination of species plus size classes were observed. IndVal showed which items were indicators of these differences. Niche breadth values were high for all species. The niche breadth values were low only for the larger size of R. quelen and Heptapterus sp. while T. poikilos values were more similar. Overall the species were a low feeding overlap values. The higher frequency of high feeding overlap was observed for interaction between Heptapterus sp. and T. poikilos. The null model confirmed the niche partitioning between the species. The higher frequency of high and intermediate feeding overlap values were reported to smaller size classes. The null model showed resource sharing between the species/size class. Therefore, overall species showed a resource partitioning because of the use of occasional items. However, these species share resources mainly in the early ontogenetic stages until the emphasized change of morphological characteristics leading to trophic niche expansion and the apparent segregation observed

Fish distribution in watersheds of the eastern part of the Serra da Mantiqueira (state of Sao Paulo)

The present work aims to analyse jointly four contiguous watersheds in the eastern part of the Serra da Mantiqueira with respect to the distribution of fish fauna and physical structure. The watersheds of Piracuama river, Ribeirao Grande, Buenos and Guaratingueta are located in Pindamonhangaba, Campos do Jordao and Guaratingueta municipalities, in the state of Sao Paulo. Data were collected between the years 2001 and 2010, with collections distributed throughout the seasons, including sites located on the slope and piedmont. The limnological parameters analysed were different between watersheds and habitat structure was different only for the slope segments between Ribeirao Grande and Buenos watersheds, and between Ribeirao Grande and Piracuama watersheds. Thirty-five species of fish were caught, with the highest species richness found in the Ribeirao Grande watershed (30 species), followed by the Piracuama (23 species) and Buenos and Guaratingueta (21 species each). The most abundant species in both the segments (slope and piedmont) was Trichomycterus itatiayae. The highest degree of species dominance occurred in the Guaratingueta watershed and in the segment slope, being T. itatiayae the dominant species. Species diversity was lower at the slope than the piedmont, indicating variability in species abundance. Again T. itatiayae was the most abundant species in both segments, showing to be a well adapted species to these streams systems by presenting, as well as other species, morphological adaptations to the stream environment.O presente trabalho tem por objetivo analisar conjuntamente quatro microbacias contíguas na serra da Mantiqueira oriental com respeito à distribuição da ictiofauna e estrutura física. As microbacias do rio Piracuama, do Ribeirão Grande, do ribeirão dos Buenos e do rio Guaratinguetá situam-se nos municípios de Pindamonhangaba, Campos do Jordão e Guaratinguetá, no estado de São Paulo. Os dados foram coletados entre os anos de 2001 e 2010, sendo as coletas distribuídas ao longo das estações e contemplando pontos localizados na encosta e no pediplano. Os parâmetros limnológicos analisados foram diferentes entre as microbacias e a estrutura de habitat foi diferente apenas para os segmentos de encosta entre as microbacias do Ribeirão Grande e Buenos, e entre Ribeirão Grande e Piracuama. Trinta e cinco espécies de peixes foram capturadas, sendo a maior riqueza de espécies encontrada na microbacia do Ribeirão Grande (30 espécies), seguida pela do rio Piracuama (23 espécies) e dos Buenos e Guaratinguetá (21 espécies cada). A espécie mais abundante tanto na encosta como pediplano foi Trichomycterus itatiayae. O maior grau de dominância de espécies ocorreu na microbacia do Guaratinguetá e no segmento de encosta, sendo T. itatiayae a espécie dominante. A diversidade de espécies para encosta foi inferior à do pediplano, indicando variabilidade na abundância das espécies. Novamente T. itatiayae foi a espécie mais abundante nos dois segmentos, espécie bem adaptada a esses sistemas de riachos por apresentar, assim como outras espécies, adaptações morfológicas ao ambiente de riachos torrentosos.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Growth and mortality of Cichla spp. (Perciformes, Cichlidae) introduced in Volta Grande Reservoir (Grande River) and in a small artificial lake in Southeastern Brazil

Os parâmetros de crescimento e mortalidade foram estimados indiretamente pelas distribuições das frequências de comprimento para espécies de Cichla spp. introduzidas em um lago em Leme (SP) e no reservatório de Volta Grande (SP-MG). em Leme, Cichla kelberi apresentou maior frequência nas classes de comprimentos inferiores, maior taxa instantânea de mortalidade natural e menor número de coortes do que C. kelberi e C. piquiti em Volta Grande. Os valores de performance de crescimento obtidos para as espécies foram próximos, corroborando a validade dos parâmetros estimados de crescimento e de mortalidade. A pressão em crescer rapidamente, devido à predação, aumenta quanto menor e menos diverso for o ambiente. O gênero Cichla adapta-se bem nos locais em que é introduzido, entretanto essa adaptação mostra-se fortemente ajustada a cada ambiente em particular, determinando com isso grande plasticidade e capacidade de estabelecimento.The growth and mortality parameters were estimated through the analysis of length frequency distribution for species of Cichla spp. introduced into a lake in Leme (SP), and in Volta Grande reservoir (SP-MG). In Leme, Cichla kelberi presented larger frequency in the inferior classes of lengths, larger instantaneous rate of natural mortality, and smaller number of cohorts than C. kelberi and C. piquiti in Volta Grande. The values of growth performance obtained for the species were similar, corroborating the validity of the estimated growth and mortality parameters. The increase of the growth rate in small and less diverse environments occurs due to predation. The genus Cichla adapts well in locations in which it is introduced, however this adaptation shows itself to be strongly adjusted to each particular location, determining great plasticity and establishment capacity

Population biology of Trichomycterus sp. (Siluriformes, Trichomycteridae) in Passa Cinco stream, Corumbataí River sub-basin, São Paulo State, southeastern Brazil

The aim of this work was to characterise the population of Trichomycterus sp. in Passa Cinco stream, regarding length structure, sex ratio, diet and reproductive aspects, in accordance with drought and rainy season periods and longitudinal gradient, as well as to analyse its corporal condition in a temporal dimension. Six samplings were accomplished with the use of electric fishing equipment in three different sites in Passa Cinco stream, contemplating sites of order two, three and four, during the months of May, July, September and November of 2005; and January and March of 2006. Three hundred and forty one individuals were captured, composed of 203 males, 99 females and 39 immatures. The smallest captured individual, an immature, presented 28 mm of standard length and the largest, a male, 85 mm. There was not significant variation in repletion degree and accumulated fat in the visceral cavity of the individuals analysed during the considered periods. Eleven different food items were found in the stomach contents. Considering the whole sampling period, immature Diptera was a preferential item and other items were found as occasionally ingested. Spearman and Friedman tests did not find significant differences in the diet of Trichomycterus sp. in the periods and sampling sites, respectively. The average of absolute fecundity was of 73 oocytes, and the parceled type of spawning was performed. Both males and females of Trichomycterus sp. presented significant differences in their corporal conditions in the considered periods, and in the rainy season, these fishes were in better condition