Microplastic ingestion in marine mesozooplankton species associated with functional feeding traits.

Microplastic (MP, <5 mm) contamination in the ocean raises concern for zooplankton, as their prey and MPs fall within the same size range. This study aimed to evaluate the ingestion capacity of MPs among a diverse array of mesozooplankton taxonomic groups and species from the central Mexican Pacific, focusing on two functional traits: trophic group and feeding strategy. A total of 20 taxa belonging to eight taxonomic groups, 13 which were identified to species level, were exposed to microspheres (Ms) ranging in size from 38 to 53 µm, at a concentration of 100 Ms/mL. All experimental treatments were placed in 620 mL bottles and rotated on a plankton wheel for 2 h. The results demonstrate that the capacity to ingest MPs is closely related to the trophic group and the feeding strategy of each species, independent of taxonomic group. Omnivores and omnivore-herbivores which generate feeding currents were the most susceptible to MPs ingestion, while highly carnivorous species with active feeding strategies were the least prone. These findings highlight the importance of evaluating MP ingestion by zooplankton at the species level, due to the variability of feeding strategies within taxonomic groups, and the need for continued trait-based research at the species level. A more detailed understanding of zooplankton feeding behavior, especially in ecologically significant species, could enhance trait-based modeling at a biogeographic scale, predicting areas with the highest risk of MP ingestion by zooplankton communities and evaluating global impacts.

Trophic plasticity of a tropical seabird revealed through DNA metabarcoding and stable isotope analyses.

DNA metabarcoding and stable isotope analysis have significantly advanced our understanding of marine trophic ecology, aiding systematic research on foraging habits and species conservation. In this study, we employed these methods to analyse faecal and blood samples, respectively, to compare the trophic ecology of two Red-billed Tropicbird (Phaethonaethereus; Linnaeus, 1758) colonies on Mexican islands in the Pacific. Trophic patterns among different breeding stages were also examined at both colonies. Dietary analysis reveals a preference for epipelagic fish, cephalopods, and small crustaceans, with variations between colonies and breeding stages. Isotopic values (δ15N and δ13C) align with DNA metabarcoding results, with wider niches during incubation stages. Differences in diet are linked to environmental conditions and trophic plasticity among breeding stages, influenced by changing physiological requirements and prey availability. Variations in dietary profiles reflect contrasting environmental conditions affecting local prey availability.

Trophic ecology of Acestrorhynchus falcirostris Cuvier, 1819 in island lakes on the lower stretch of the Solimões River, Amazon Basin

Abstract The aim objective of this study was to determine the trophic ecology of juvenile and adult Acestrorhynchus falcirostris during the rising and flood (high-water) period in six island lakes adjacent to the Solimões River. As such, we investigated: i) the trophic position, through the fractional trophic niche; ii) the niche breadth; iii) niche overlap and iv) the food strategy of the species. The specimens were collected during the years 2014 to 2017, using gillnets with mesh sizes ranging from 30 to 120mm between opposite knots. Through the analysis of stomach contents, the preference in the consumption of items of animal origin was observed. Juveniles consumed insects in greater proportions (IAi% = 50%), while adults consumed fish (IAi%=99,98%). Despite the large supply of food items available in the high-water period, juveniles were the only ones to consume items of allochthonous origin, such as insects. Juveniles presented a different dietary strategy and dietary composition to adults. Juveniles were omnivores with a generalist strategy, while adults were piscivores with a specialist strategy. Thus, the food composition, niche breadth, trophic position and feeding strategy of Acestrorhynchus falcirostris change due to the stage of development.

Resumo O objetivo deste estudo foi determinar a ecologia trófica de juvenis e adultos de Acestrorhynchus falcirostris durante o período de enchente e cheia em seis lagos de ilha adjacentes ao rio Solimões. Assim, investigamos: i) a posição trófica, através do nicho trófico fracional; ii) a largura de nicho; iii) sobreposição de nicho; iv) a estratégia alimentar. Os espécimes foram coletados durante os anos de 2014 a 2017, utilizando redes de emalhar com malha variando de 30 a 120mm entre nós opostos. Por meio da análise do conteúdo estomacal, observamos a preferência no consumo de itens de origem animal. Os juvenis consumiram insetos em maiores proporções (IAi% = 50%), enquanto os adultos consumiram preferencialmente peixes (IAi% = 99,98%). Apesar da grande oferta de alimentos disponíveis no período da cheia, os juvenis eram os únicos a consumir itens de origem alóctone, como por exemplo, os insetos. Os juvenis apresentaram uma estratégia alimentar e composição alimentar diferente para os adultos. Os juvenis foram considerados onívoros com uma estratégia generalista, enquanto os adultos foram considerados piscívoros com uma estratégia alimentar mais especialista. Assim, a composição alimentar, amplitude do nicho, posição trófica e a estratégia alimentar de Acestrorhynchus falcirostris muda em função do estágio de desenvolvimento.

Trophic ecology of Acestrorhynchus falcirostris Cuvier, 1819 in island lakes on the lower stretch of the Solimões River, Amazon Basin / Ecologia trófica de Acestrorhynchus falcirostris Cuvier, 1819 em lagos de ilha no trecho inferior do Rio Solimões, Bacia Amazônica

Abstract The aim objective of this study was to determine the trophic ecology of juvenile and adult Acestrorhynchus falcirostris during the rising and flood (high-water) period in six island lakes adjacent to the Solimões River. As such, we investigated: i) the trophic position, through the fractional trophic niche; ii) the niche breadth; iii) niche overlap and iv) the food strategy of the species. The specimens were collected during the years 2014 to 2017, using gillnets with mesh sizes ranging from 30 to 120mm between opposite knots. Through the analysis of stomach contents, the preference in the consumption of items of animal origin was observed. Juveniles consumed insects in greater proportions (IAi% = 50%), while adults consumed fish (IAi%=99,98%). Despite the large supply of food items available in the high-water period, juveniles were the only ones to consume items of allochthonous origin, such as insects. Juveniles presented a different dietary strategy and dietary composition to adults. Juveniles were omnivores with a generalist strategy, while adults were piscivores with a specialist strategy. Thus, the food composition, niche breadth, trophic position and feeding strategy of Acestrorhynchus falcirostris change due to the stage of development.

Resumo O objetivo deste estudo foi determinar a ecologia trófica de juvenis e adultos de Acestrorhynchus falcirostris durante o período de enchente e cheia em seis lagos de ilha adjacentes ao rio Solimões. Assim, investigamos: i) a posição trófica, através do nicho trófico fracional; ii) a largura de nicho; iii) sobreposição de nicho; iv) a estratégia alimentar. Os espécimes foram coletados durante os anos de 2014 a 2017, utilizando redes de emalhar com malha variando de 30 a 120mm entre nós opostos. Por meio da análise do conteúdo estomacal, observamos a preferência no consumo de itens de origem animal. Os juvenis consumiram insetos em maiores proporções (IAi% = 50%), enquanto os adultos consumiram preferencialmente peixes (IAi% = 99,98%). Apesar da grande oferta de alimentos disponíveis no período da cheia, os juvenis eram os únicos a consumir itens de origem alóctone, como por exemplo, os insetos. Os juvenis apresentaram uma estratégia alimentar e composição alimentar diferente para os adultos. Os juvenis foram considerados onívoros com uma estratégia generalista, enquanto os adultos foram considerados piscívoros com uma estratégia alimentar mais especialista. Assim, a composição alimentar, amplitude do nicho, posição trófica e a estratégia alimentar de Acestrorhynchus falcirostris muda em função do estágio de desenvolvimento.

Prandial Correlations and Structure of the Ingestive Behavior of Pigs in Precision Feeding Programs.

The feeding behavior of growing-finishing pigs was analyzed to study prandial correlations and the probability of starting a new feeding event. The data were collected in real-time based on 157,632 visits by a group of 70 growing-finishing pigs (from 30.4 to 115.5 kg body weight, BW) to automatic feeders. The data were collected over 84 days, during which period the pigs were kept in conventional (by phase and by group) or precision (with daily and individual adjustments) feeding programs. A criterion to delimit each meal was then defined based on the probability of an animal starting a new feeding event within the next minute since the last visit. Prandial correlations were established between meal size and interval before meal (pre-prandial) or interval after meal (post-prandial) using Pearson correlation analysis. Post-prandial correlations (which can be interpreted as hunger-regulating mechanisms) were slightly stronger than pre-prandial correlations (which can be interpreted as satiety regulation mechanisms). Both correlations decreased as the animals' age increased but were little influenced by the feeding programs. The information generated in this study allows a better understanding of pigs' feeding behavior regulation mechanisms and could be used in the future to improve precision feeding programs.

Head adaptation for sound production and feeding strategy in dolphins (Odontoceti: Delphinida).

Head morphology in toothed whales evolved under selective pressures on feeding strategy and sound production. The postnatal development of the skull (n = 207) and mandible (n = 219) of six Delphinida species which differ in feeding strategy but exhibit similar sound emission patterns, including two narrow-band high-frequency species, were investigated through 3D morphometrics. Morphological changes throughout ontogeny were demonstrated based on the main source of variation (i.e., prediction lines) and the common allometric component. Multivariate trajectory analysis with pairwise comparisons between all species was performed to evaluate specific differences on the postnatal development of skulls and mandibles. Changes in the rostrum formation contributed to the variation (skull: 49%; mandible: 90%) of the entire data set and might not only reflect the feeding strategy adopted by each lineage but also represents an adaptation for sound production and reception. As an important structure for directionality of sound emissions, this may increase directionality in raptorial feeders. Phylogenetic generalized least squares analyses indicated that shape of the anterior portion of the skull is strongly dependent on phylogeny and might not only reflect feeding mode, but also morphological adaptations for sound production, particularly in raptorial species. Thus, postnatal development seems to represent a crucial stage for biosonar maturation in some raptorial species such as Pontoporia blainvillei and Sousa plumbea. The ontogeny of their main tool for navigation and hunting might reflect their natural history peculiarities and thus potentially define their main vulnerabilities to anthropogenic changes in the environment.

Effect of timing of corn silage supplementation to Holstein dairy cows given limited daily access to pasture: intake and performance.

The timing in which supplements are provided in grazing systems can affect dry matter (DM) intake and productive performance. The objective of this study was to evaluate the effect of timing of corn silage supplementation on ingestive behaviour, DM intake, milk yield and composition in grazing dairy cows. In total, 33 Holstein dairy cows in a randomized block design grazed on a second-year mixed grass-legume pasture from 0900 to 1500 h and received 2.7 kg of a commercial supplement at each milking. Paddock sizes were adjusted to provide a daily herbage allowance of 15 kg DM/cow determined at ground level. The three treatments imposed each provided 3.8 kg DM/day of corn silage offered in a single meal at 0800 h (Treatment AM), equally distributed in two meals 0800 and 1700 h (Treatment AM-PM) or a single meal at 1700 h (Treatment PM). The experiment was carried out during the late autumn and early winter period, with 1 week of adaptation and 6 weeks of measurements. There were no differences between treatments in milk yield, but 4% fat-corrected milk yield tended to be greater in AM-PM than in AM cows, which did not differ from PM (23.7, 25.3 and 24.6±0.84 kg/day for AM, AM-PM and PM, respectively). Fat percentage and yield were greater for AM-PM than for AM cows and intermediate for PM cows (3.89 v. 3.66±0.072% and 1.00 v. 0.92±0.035 kg/day, respectively). Offering corn silage in two meals had an effect on herbage DM intake which was greater for AM-PM than AM cows and was intermediate in PM cows (8.5, 11.0 and 10.3±0.68 kg/day for AM, AM-PM and PM, respectively). During the 6-h period at pasture, the overall proportion of observations on which cows were grazing tended to be different between treatments and a clear grazing pattern along the grazing session (1-h observation period) was identified. During the time at pasture, the proportion of observations during which cows ruminated was positively correlated with the DM intake of corn silage immediately before turn out to pasture. The treatment effects on herbage DM intake did not sufficiently explain differences in productive performance. This suggests that the timing of the corn silage supplementation affected rumen kinetics and likewise the appearance of hunger and satiety signals as indicated by observed changes in temporal patterns of grazing and ruminating activities.

Feeding habits of cobia in Pernambuco, northeastern Brazil / Hábito alimentar do beijupirá em Pernambuco, Nordeste do Brasil

The feeding habits of cobia, Rachycentron canadum, was described along the coast of Pernambuco State, northeastern Brazil. One hundred ten specimens were caught between February 2004 and August 2006 with fork length ranging from 40.0 to 137.0 cm (mean and standard deviation: 85.8 ± 18.0 cm) and total weight between 0.4 and 29.8 kg (7.5 ± 4.4 kg). The importance of each food item in the diet was evaluated using the index of relative importance (IRI). Among the one hundred ten stomachs analyzed (52 females and 58 males), 92 (83.6%) had food items, while 18 (16.4%) were empty. Bony fish were the main food item (IRI = 98.7%), being squirrelfish (Holocentrus adscensionis) and porcupine fish (Diodon sp.) the most frequent prey items (30.7% and 8.2%, respectively). Elasmobranchs, crustaceans and cephalopods were also present in small proportions (IRI < 1% for each). No significant differences in diet were found between sexes or size classes (fork length: < or ≥ 69.8 cm; estimated L50 for the species). The present data demonstrate that cobia is a carnivorous predator along the coast of Pernambuco State, with a preference for demersal bony fish, independently of the size and sex of the individuals analyzed.(AU)

O hábito alimentar do beijupirá, Rachycentron canadum, foi descrito ao longo da costa do Estado de Pernambuco, Nordeste do Brasil. Foram capturados 110 exemplares entre fevereiro/2004 e agosto/2006, com comprimento furcal ou zoológico variando entre 40,0 e 137,0 cm (média e desvio padrão: 85,8±18,0 cm) e peso total entre 0,4 e 29,8 kg (7,5±4,4 kg). Foi avaliada a importância de cada item alimentar na dieta utilizando o índice de importância relativa (IIR). Dentre os 110 estômagos analisados (52 fêmeas e 58 machos), 92 (83,6%) com algum item alimentar e 18 (16,4%) vazios. Os peixes ósseos foram os principais itens consumidos na dieta alimentar (IIR = 98,7%), entre os quais a mariquita (Holocentrus adscensionis) e o baiacu (Diodon sp.) foram as presas mais consumidas (IIR = 30,7% e 8,2%, respectivamente). A dieta foi composta, ainda, por elasmobrânquios, crustáceos e cefalópodes (IIR <1% cada). Não foram encontradas diferenças na dieta entre os sexos e classes de tamanho (< ou ≥ 69,8 cm de comprimento furcal, L50 estimado para a espécie). Os dados analisados demonstram que, na costa de Pernambuco, o beijupirá é um predador carnívoro com preferência por peixes ósseos demersais, independente do tamanho e sexo dos indivíduos analisados.(AU)

Feeding habits of cobia in Pernambuco, northeastern Brazil / Hábito alimentar do beijupirá em Pernambuco, Nordeste do Brasil

The feeding habits of cobia, Rachycentron canadum, was described along the coast of Pernambuco State, northeastern Brazil. One hundred ten specimens were caught between February 2004 and August 2006 with fork length ranging from 40.0 to 137.0 cm (mean and standard deviation: 85.8 ± 18.0 cm) and total weight between 0.4 and 29.8 kg (7.5 ± 4.4 kg). The importance of each food item in the diet was evaluated using the index of relative importance (IRI). Among the one hundred ten stomachs analyzed (52 females and 58 males), 92 (83.6%) had food items, while 18 (16.4%) were empty. Bony fish were the main food item (IRI = 98.7%), being squirrelfish (Holocentrus adscensionis) and porcupine fish (Diodon sp.) the most frequent prey items (30.7% and 8.2%, respectively). Elasmobranchs, crustaceans and cephalopods were also present in small proportions (IRI < 1% for each). No significant differences in diet were found between sexes or size classes (fork length: < or ≥ 69.8 cm; estimated L50 for the species). The present data demonstrate that cobia is a carnivorous predator along the coast of Pernambuco State, with a preference for demersal bony fish, independently of the size and sex of the individuals analyzed.

O hábito alimentar do beijupirá, Rachycentron canadum, foi descrito ao longo da costa do Estado de Pernambuco, Nordeste do Brasil. Foram capturados 110 exemplares entre fevereiro/2004 e agosto/2006, com comprimento furcal ou zoológico variando entre 40,0 e 137,0 cm (média e desvio padrão: 85,8±18,0 cm) e peso total entre 0,4 e 29,8 kg (7,5±4,4 kg). Foi avaliada a importância de cada item alimentar na dieta utilizando o índice de importância relativa (IIR). Dentre os 110 estômagos analisados (52 fêmeas e 58 machos), 92 (83,6%) com algum item alimentar e 18 (16,4%) vazios. Os peixes ósseos foram os principais itens consumidos na dieta alimentar (IIR = 98,7%), entre os quais a mariquita (Holocentrus adscensionis) e o baiacu (Diodon sp.) foram as presas mais consumidas (IIR = 30,7% e 8,2%, respectivamente). A dieta foi composta, ainda, por elasmobrânquios, crustáceos e cefalópodes (IIR <1% cada). Não foram encontradas diferenças na dieta entre os sexos e classes de tamanho (< ou ≥ 69,8 cm de comprimento furcal, L50 estimado para a espécie). Os dados analisados demonstram que, na costa de Pernambuco, o beijupirá é um predador carnívoro com preferência por peixes ósseos demersais, independente do tamanho e sexo dos indivíduos analisados.

Tidal-diel patterns in feeding and abundance of armed snook Centropomus armatus from macrotidal mangrove creeks of the tropical eastern Pacific Ocean.

We investigated the influence of temporal and spatial factors on the feeding habits of the armed snook Centropomus armatus (Centropomidae), the most abundant snook species in eastern Pacific mangrove ecosystems. The influence of the combination of semi-diurnal tides and diel cycles and salinity on the intertidal abundance, stomach fullness, diet composition and daily consumption of this species was investigated over 1 year in the macrotidal Colombian Pacific coast (Bahía Málaga). The abundance of juvenile C. armatus (5.6-23.6 cm total length) in the intertidal creeks was highest during neap tide-night conditions and lowest during spring-tide day conditions. Centropomus armatus fed predominantly on crustaceans (Alpheidae and Palaemonidae) and fishes. Stomach fullness index (ISF ), a proxy of feeding activity, was not influenced by salinity, but by tidal-diel conditions. Stomach fullness index was highest during neap tide nocturnal inundations, but lowest during diurnal neap tides. Nevertheless, the total daily consumption was higher at spring tide than at neap tides. Higher water temperatures in creeks during neap tides at night could explain not only high C. armatus abundance, but also greater accessibility to active prey. Comparison with the feeding patterns of fishes from other macrotidal mangrove ecosystems suggest that the habitat use and feeding patterns of intertidal fishes in mangroves are strongly influenced by the combination of spring-neap tide and diel cycles. However, the interaction between mangrove geomorphology and flooding regime of the specific mangrove forest might also play a role and deserves further investigation.

Food deprivation does not affect growth performance of juvenile tambacu / Privação alimentar não afeta o crescimento de juvenis de tambacu

The objective of this study was to evaluate the efficiency of food deprivation on the growth performance of the commercially important hybrid fish tambacu (Piaractus mesopotamicus male × Colossoma macropomum female). For this, 171 juveniles of average length 8 cm and 11.4 g body mass were distributed in nine tanks, and allocated to three treatments: the fish were fed every day (control), fed for six days followed by one day of food deprivation (6F/1D) and fed for five days followed by two days of food deprivation (5F/2D). After 77 days, all animals achieved similar growth rates. Only animals submitted to two days of food deprivation presented hyperphagia. There was a reduction in total feed consumption of 3.8% and 10.8% for the 6F/1D and 5F/2D treatments, respectively. Our results suggest that juvenile tambacu exhibit total compensatory growth when submitted to food deprivation, and that a two-day deprivation could significantly reduce production costs for tambacu farmers.(AU)

O objetivo do estudo foi avaliar a eficiência da privação alimentar sobre o desempenho zootécnico de tambacu (Piaractus mesopotamicus x Colossoma macropomum). Para isso, 171 animais (massa: 11,4 ± 1.5 g; comprimento total: 8.0 ± 0.4 cm) foram alocados em nove tanques (19 peixes/tanque; n=3). Os peixes foram alimentados todos os dias (controle), alimentados durante seis dias seguidos de um dia de privação alimentar (6F/1D) e durante cinco dias seguidos de dois dias de privação alimentar (5F/2D). Após 77 dias, todos os animais alcançaram índices de crescimento similares. Somente os animais submetidos a dois dias de privação apresentaram hiperfagia. Houve redução do consumo total de ração em 3,8 e 10,8% para os tratamentos 6F/1D e 5F/2D, respectivamente. Os nossos resultados demonstram que os juvenis de tambacu exibiram crescimento compensatório total quando submetidos a privação alimentar, e a estratégia de 2 dias de privação alimentar pode reduzir significativamente os custos de produção de tambacu.(AU)

Food deprivation does not affect growth performance of juvenile tambacu / Privação alimentar não afeta o crescimento de juvenis de tambacu

The objective of this study was to evaluate the efficiency of food deprivation on the growth performance of the commercially important hybrid fish tambacu (Piaractus mesopotamicus male × Colossoma macropomum female). For this, 171 juveniles of average length 8 cm and 11.4 g body mass were distributed in nine tanks, and allocated to three treatments: the fish were fed every day (control), fed for six days followed by one day of food deprivation (6F/1D) and fed for five days followed by two days of food deprivation (5F/2D). After 77 days, all animals achieved similar growth rates. Only animals submitted to two days of food deprivation presented hyperphagia. There was a reduction in total feed consumption of 3.8% and 10.8% for the 6F/1D and 5F/2D treatments, respectively. Our results suggest that juvenile tambacu exhibit total compensatory growth when submitted to food deprivation, and that a two-day deprivation could significantly reduce production costs for tambacu farmers.

O objetivo do estudo foi avaliar a eficiência da privação alimentar sobre o desempenho zootécnico de tambacu (Piaractus mesopotamicus x Colossoma macropomum). Para isso, 171 animais (massa: 11,4 ± 1.5 g; comprimento total: 8.0 ± 0.4 cm) foram alocados em nove tanques (19 peixes/tanque; n=3). Os peixes foram alimentados todos os dias (controle), alimentados durante seis dias seguidos de um dia de privação alimentar (6F/1D) e durante cinco dias seguidos de dois dias de privação alimentar (5F/2D). Após 77 dias, todos os animais alcançaram índices de crescimento similares. Somente os animais submetidos a dois dias de privação apresentaram hiperfagia. Houve redução do consumo total de ração em 3,8 e 10,8% para os tratamentos 6F/1D e 5F/2D, respectivamente. Os nossos resultados demonstram que os juvenis de tambacu exibiram crescimento compensatório total quando submetidos a privação alimentar, e a estratégia de 2 dias de privação alimentar pode reduzir significativamente os custos de produção de tambacu.

Incorporation of zinc and copper by insects of different functional feeding groups in agricultural streams.

Metals from agricultural areas are responsible for soil contamination and are carried into aquatic ecosystems. In this context, we evaluated the incorporation of zinc and copper via three feeding strategies (shredding, herbivory and predators) in assemblages of stream insects. We collected aquatic insects in five agricultural streams and five natural streams in Atlantic forest biome to investigate the accumulation of copper and zinc in insects with different feeding strategies. We found no significant differences in the concentrations of copper and zinc between stream types among all insect-feeding groups compared. However, we observed that copper accumulate concentrations differed significantly among the shredders and predators in relation to their resource in streams, while zinc concentrations differed in the two feeding strategy. Therefore, the investigation of the transfer of copper and zinc by different feeding strategies in streams can contribute to the understanding of changes in aquatic insect assemblages related to agricultural activities around streams.

The feeding habits of the endemic Remo flounder, Oncopterus darwinii (Actinopterygii: Pleuronectidae), in an exposed sandy beach's surf zone in southern Brazil

The Remo flounder, Oncopterus darwinii Steindachner, 1874 is a small Pleuronectidae (~ 250 mm TL) distributed in the warm-temperate zone from Santa Catarina (28°S - Brazil) to the Gulf of San Matías (42°S - Argentina). We studied the occurrence and diet of juveniles of this flatfish (85% < 100 mm TL) for one year (August 2009 to July 2010) in a southern Brazilian sandy beach. Individuals were much more common in spring and early summer than in the other seasons. Of the 758 individuals analyzed, only 69 (9.1%) were found with empty stomachs. The Remo flounder fed predominantly on small crustaceans (gammarid amphipods, mysids and the hipiidae Emerita brasiliensis Schmitt, 1935) and no seasonal differences were found in the composition of the diet of this flatfish. However, variations in the Index of Relative Importance (IRI) were found among seasons, which most likely can be explained by a decrease in the availability of favored food items throughout the year. The pattern of distribution of O. darwinii indicates that southern Brazilian sandy beaches are used as nursery ground for this species.

The feeding habits of the endemic Remo flounder, Oncopterus darwinii (Actinopterygii: Pleuronectidae), in an exposed sandy beach's surf zone in southern Brazil

The Remo flounder, Oncopterus darwinii Steindachner, 1874 is a small Pleuronectidae (~ 250 mm TL) distributed in the warm-temperate zone from Santa Catarina (28°S - Brazil) to the Gulf of San Matías (42°S - Argentina). We studied the occurrence and diet of juveniles of this flatfish (85% < 100 mm TL) for one year (August 2009 to July 2010) in a southern Brazilian sandy beach. Individuals were much more common in spring and early summer than in the other seasons. Of the 758 individuals analyzed, only 69 (9.1%) were found with empty stomachs. The Remo flounder fed predominantly on small crustaceans (gammarid amphipods, mysids and the hipiidae Emerita brasiliensis Schmitt, 1935) and no seasonal differences were found in the composition of the diet of this flatfish. However, variations in the Index of Relative Importance (IRI) were found among seasons, which most likely can be explained by a decrease in the availability of favored food items throughout the year. The pattern of distribution of O. darwinii indicates that southern Brazilian sandy beaches are used as nursery ground for this species.(AU)

Fortifying pork liver mixture: Evaluation of protein quality and iron bioavailability - Part 2 / Mistura fortificadora a base de fígado suíno: avaliação da qualidade protéica e da biodisponibilidade de ferro - Parte 2

ABSTRACT Objective To evaluate the protein quality and iron bioavailability of a fortifying mixture based on pork liver. Methods Determinations of protein efficiency ratio, net protein utilization, true digestibility and hemoglobin regeneration efficiency by depletion and repletion were performed. In the depletion phase, the animals (male Wistar rats) received an iron-free AIN-93G diet and in the repletion phase they received the following diets: standard AIN-93G diet, fortifying mixture and standard diet containing heptahydrated ferrous sulfate for comparison. Results For standard AIN-93G diet and fortifying mixture the results were 3.75 and 4.04 for protein efficiency ratio and 3.53 and 3.63 for net protein retention, showing that the presence of pork liver in the diet promoted an increase in protein efficiency ratio and net protein retention (not statistically significant). True digestibility results obtained with the fortifying mixture (97.16%) were higher than those obtained with the standard AIN-93G diet (casein), but without significant difference. The hemoglobin regeneration efficiency values obtained for standard AIN-93G diet, fortifying mixture and standard diet containing heptahydrated ferrous sulfate were 50.69, 31.96 and 29.96%, respectively, showing a statistically significant difference between the control (standard AIN-93G diet) and test (fortifying mixture and standard diet containing heptahydrated ferrous sulfate) samples, but not between the test samples. Conclusion The fortifying mixture showed a high protein efficiency ratio value of 4.04 and a high relative biological value (108%) and it can be added to soups, creams and meats in day-care centers for the prevention of iron-deficiency in children of school age.

RESUMO Objetivo Avaliar a qualidade protéica e a biodisponibilidade de ferro de uma mistura fortificadora a base de fígado suíno. Métodos Foram determinados coeficiente de eficácia protéica, retenção protéica líquida, digestibilidade verdadeira e de eficiência da regeneração de hemoglobina (depleção e repleção). Na fase de depleção os animais (ratos da linhagem Wistar) receberam dieta (AIN-93G) isenta de ferro e na fase de repleção receberam as dietas: padrão AIN-93G (dietas padrão AIN-93G), mistura fortificadora e dieta-padrão com sulfato ferroso heptahidratado para comparação. Resultados Para dietas padrão AIN-93G e mistura fortificadora os resultados foram respectivamente 3,75 e 4,04 para coeficiente de eficácia protéica e 3,53 e 3,63 para retenção protéica líquida mostrando que a presença de fígado suíno promoveu aumento dos valores de coeficiente de eficácia protéica e retenção protéica líquida (sem diferença estatística). Resultados de digestibilidade verdadeira obtidos com a dieta mistura fortificadora (97,16%) foram maiores do que os obtidos com a dietas padrão AIN-93G (caseína), também sem diferença estatística. Os resultados de eficiência da regeneração de hemoglobina para dietas padrão AIN-93G, mistura fortificadora e sulfato ferroso heptahidratado foram respectivamente 50,69; 31,96 e 29,96% apresentando diferença estatística significativa entre a amostra controle (dietas padrão AIN-93G) e as amostras testes (mistura fortificadora e sulfato ferroso heptahidratado), porém não entre as amostras testes. Conclusão A mistura fortificadora se mostrou com alto coeficiente de eficácia protéica (4,04) e alto valor biológico relativo (108%) podendo ser adicionada às sopas, cremes, carnes em creches na prevenção e controle da anemia ferropriva em crianças em idade escolar.

The partitioning of food resources between two rodents in the subtropical region of southern Brazil

ABSTRACT The capybara (Hydrochoerus hydrochaeris) and nutria (Myocastor coypus) are herbivorous semi-aquatic rodents. Although these rodents occur in sympatry in southern South America, little is known about how the two species interact in relationship to food resources. In this context, the aim of this study was to analyze the food resource overlap, the feeding strategy and the diversity of the diet of capybaras and nutria. A micro-histological analysis of feces was used to study the diets. A total of 48 plant species belonging to 10 families were identified in the diet of H. hydrochaeris, and a total of 49 species belonging to 14 families were identified in the diet of M. coypus. According to the Amundsen graphical method, both rodents adopted a specialized strategy for feeding on Poaceae and a generalized strategy for other families. The results of a multivariate analysis of the dietary data showed significant differences between the two rodent species and among the seasons. These differences between diets may be related to the different proportions of each food item eaten. However, the dietary overlap between the two rodents in the Taim wetland was high, suggesting that partitioning of other resources ensured the coexistence of the species.

Feeding habits of billfishes (Carangaria: Istiophoriformes) in the Ecuadorian Pacific Ocean

The feeding habits of Makaira nigricans, Kajikia audax, Istiophorus platypterus (Istiophoridae), and Xiphias gladius (Xiphiidae) in the southeast Pacific Ocean were examined in Manta and Santa Rosa, Ecuador. This study describes the diets of these billfish species, evaluates dietary differences between species, and assesses seasonal differences in diet. A total of 274 M. nigricans, 321 K. audax, 267 I. platypterus, and 252 X. gladius were collected between February 2014 and April 2015. The scombrid Auxis spp. was the most important prey for M. nigricans, K. audax and I. platypterus, while the squid Dosidicus gigas was the most important prey for X. gladius. The results of the ANOSIM confirmed significant differences in feeding habits between the members of the family Istiophoridae and X. gladius. Seasonal differences for I. platypterus also were observed. Billfishes are specialist consumers with a narrow niche breadth (B a: M. nigricans and K. audax=0.1, I. platypterus=0.05, and X. gladius=0.04).(AU)

Los hábitos alimentarios de Makaira nigricans, Kajikia audax, Istiophorus platypterus (Istiophoridae) y Xiphias gladius (Xiphiidae) en el Océano Pacífico sudeste se examinaron en Manta y Santa Rosa, Ecuador. Este estudio describe las dietas de estas especies de peces de pico, evalúa las diferencias de la dieta entre especies y las diferencias estacionales en la dieta. Se obtuvo un total de 274 M. nigricans, 321 K. audax, 267 I. platypterus y 252 X. gladius entre febrero 2014 y abril 2015. El escómbrido Auxis spp. fue la presa más importante para M. nigricans, K. audax y I. platypterus, mientras que el calamar Dosidicus gigas fue la presa más importante para X. gladius. Los resultados de ANOSIM confirmaron diferencias significativas en los hábitos alimentarios entre los miembros de la familia Istiophoridae y X. gladius. También se observaron diferencias estacionales para I. platypterus. Los peces de pico son consumidores especialistas con una amplitud de nicho estrecha (B a: M. nigricans y K. audax=0.1, I. platypterus=0.05 y X.gladius=0.04).(AU)

Ontogenetic variations and feeding habits of a Neotropical annual fish from southern Brazil / Variações ontogenéticas e hábitos alimentares de um peixe anual Neotropical do sul do Brasil

Knowing the feeding biology of a population and its ontogenetic aspects can help in understanding the functioning of fish assemblages, essential to the conservation of the habitat biodiversity in which these species are found. Annual fishes complete their life cycle in temporary aquatic environments, existing in adult stage only for brief annual periods. Changes in the feeding habits between different size classes could indicate that a species belongs to different feeding groups in different growth phases. The aim of this work was to characterize the diet of Cynopoecilus fulgens Costa, 2002 in a temporary flooded area in the coastal plain of southern Brazil, taking into consideration possible alterations in feeding habits in different body size classes caused by ontogenetic changes, to explain the coexistence of these individuals in a short space of time. The diet analysis indicated that C. fulgens is a generalist, consuming small crustaceans and autochthonous insects. Intraspecific differences in diet were determined when compared between nine classes of standard length. Adults fed mainly on autochthonous insects, and juveniles ingested mostly crustaceans, with the population being separated into two trophic groups: invertivores and invertivores with a tendency towards zooplanktivory. It is possible to conclude that the ontogenetic changes in the diet of C. fulgens are related to morphological restrictions due to the size of the individuals, since feeding competitive relations are probably not so evident.(AU)

Conhecer a biologia alimentar de uma população e seus aspectos ontogenéticos podem auxiliar na compreensão do funcionamento de assembleias de peixes, fundamental para a conservação da biodiversidade do habitat no qual estas espécies são encontradas. Peixes anuais completam seu ciclo de vida em ambientes aquáticos temporários, sendo encontrados no estágio adulto somente em breves períodos anuais. Mudanças nos hábitos alimentares entre diferentes classes de tamanho podem indicar que uma espécie pertence a distintos grupos alimentares nas diferentes fases do crescimento. Este trabalho teve como objetivo caracterizar a dieta de Cynopoecilus fulgens Costa, 2002 em uma área temporariamente alagada na planície costeira sul-riograndense, levando em consideração possíveis alterações nos hábitos alimentares nas diferentes classes de tamanho corporal causadas por mudanças ontogenéticas, visando explicar a coexistência destes indivíduos em um curto espaço de tempo. A análise da dieta indica que C. fulgens é uma espécie generalista, ingerindo pequenos crustáceos e insetos autóctones. Diferenças intraespecíficas na composição da dieta foram verificadas quando comparadas entre as nove classes de comprimento padrão estabelecidas. Adultos se alimentaram principalmente de insetos autóctones, enquanto os juvenis ingeriram principalmente crustáceos, sendo a população separada em dois grupos tróficos: invertívoros e invertívoros com tendência à zooplanctivoria. É possível concluir que as mudanças ontogenéticas na dieta de C. fulgens estejam relacionadas a restrições morfológicas decorrentes do tamanho dos indivíduos, já que as relações competitivas, em termos alimentares, não são aparentemente tão evidentes.(AU)

Ontogenetic variations and feeding habits of a Neotropical annual fish from southern Brazil / Variações ontogenéticas e hábitos alimentares de um peixe anual Neotropical do sul do Brasil

Knowing the feeding biology of a population and its ontogenetic aspects can help in understanding the functioning of fish assemblages, essential to the conservation of the habitat biodiversity in which these species are found. Annual fishes complete their life cycle in temporary aquatic environments, existing in adult stage only for brief annual periods. Changes in the feeding habits between different size classes could indicate that a species belongs to different feeding groups in different growth phases. The aim of this work was to characterize the diet of Cynopoecilus fulgens Costa, 2002 in a temporary flooded area in the coastal plain of southern Brazil, taking into consideration possible alterations in feeding habits in different body size classes caused by ontogenetic changes, to explain the coexistence of these individuals in a short space of time. The diet analysis indicated that C. fulgens is a generalist, consuming small crustaceans and autochthonous insects. Intraspecific differences in diet were determined when compared between nine classes of standard length. Adults fed mainly on autochthonous insects, and juveniles ingested mostly crustaceans, with the population being separated into two trophic groups: invertivores and invertivores with a tendency towards zooplanktivory. It is possible to conclude that the ontogenetic changes in the diet of C. fulgens are related to morphological restrictions due to the size of the individuals, since feeding competitive relations are probably not so evident.

Conhecer a biologia alimentar de uma população e seus aspectos ontogenéticos podem auxiliar na compreensão do funcionamento de assembleias de peixes, fundamental para a conservação da biodiversidade do habitat no qual estas espécies são encontradas. Peixes anuais completam seu ciclo de vida em ambientes aquáticos temporários, sendo encontrados no estágio adulto somente em breves períodos anuais. Mudanças nos hábitos alimentares entre diferentes classes de tamanho podem indicar que uma espécie pertence a distintos grupos alimentares nas diferentes fases do crescimento. Este trabalho teve como objetivo caracterizar a dieta de Cynopoecilus fulgens Costa, 2002 em uma área temporariamente alagada na planície costeira sul-riograndense, levando em consideração possíveis alterações nos hábitos alimentares nas diferentes classes de tamanho corporal causadas por mudanças ontogenéticas, visando explicar a coexistência destes indivíduos em um curto espaço de tempo. A análise da dieta indica que C. fulgens é uma espécie generalista, ingerindo pequenos crustáceos e insetos autóctones. Diferenças intraespecíficas na composição da dieta foram verificadas quando comparadas entre as nove classes de comprimento padrão estabelecidas. Adultos se alimentaram principalmente de insetos autóctones, enquanto os juvenis ingeriram principalmente crustáceos, sendo a população separada em dois grupos tróficos: invertívoros e invertívoros com tendência à zooplanctivoria. É possível concluir que as mudanças ontogenéticas na dieta de C. fulgens estejam relacionadas a restrições morfológicas decorrentes do tamanho dos indivíduos, já que as relações competitivas, em termos alimentares, não são aparentemente tão evidentes.