Search

An experimental study was undertaken to assess the impact of substrate and periphyton on the growth, survival and feed utilization of Penaeus vannamei. This study was conducted in cement tanks with bamboo as substrate. The average submersion depth of the substrates was maintained at 85.16 ± 0.26 cm in the treatment tanks. There was significant difference (P value < 0.05) observed in the values of Chlorophyll a (3.12 ± 0.32 µg/cm2 minimum and 16.29 ± 1.15 µg/cm2 maximum values), dry weight (2.49 ± 1.46 mg/cm2), ash (0.78 ± 0.46 mg/cm2), ash free dry weight (1.71 ± 1.0 mg/cm2) and autotrophic index (146 ± 18) in terms of submersion time but there was no significance observed in terms of substrate depth. The bio growth parameters (Average Body Weight - 15.4 ± 4.9 g, Average Daily Growth - 0.165 ± 0.01 g, Specific Growth Rate - 7.67 ± 0.03, Protein Efficiency Ratio - 3.12 ± 0.15 and Food Conversion Ratio - 0.92 ± 0.00018) were also observed to be high in treatments with the substrate. Feed usage in the treatment tank was found to be reduced by 19% compared to the control tank. The Periphyton community recorded on the treatment tanks with split bamboo poles as substrate comprised of 4 groups (Bacillariophyceae, Chlorophyceae, Cyanophyceae and Euglenophyceae). The results on the depth-wise analysis of microbial load on the split bamboo substrate have shown a significant difference between 10 cm and 40 cm depth and 10 cm and 70 cm depth of the substrate (P<0.05), whereas, there was no significance observed between 40 cm and 70 cm depth of the substrate in the microbial load. Under the low saline condition, substrate-based vannamei farming has shown better performance compared to the tanks without substrate. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract For the proper growth of fish, it is necessary to feed the fish with a proper and balanced diet. A study was conducted to find out the effect of different protein-based diets on fingerlings of Tor putitora (mahseer). A feed with dietary protein levels of 35%, 40%, 45%, and 50% were prepared. The effect of different protein-based feed on weight gain, standard growth rate (SGR), food conversion ratio (FCR), percent weight gain, food conversion efficiency (FCE), and protein efficiency ratio (PER) was studied. An increase was observed in the growth rate with an increase in protein concentration up to 45%. The fingerlings fed a 45% protein diet shown the highest growth, followed by 50%, 40%, and 35%. The SGR value was greatest for 45% protein diet (8.56) followed by 50% and 40%, while the least values were observed for 35% protein feed (1.57). The same trend was observed for FCE. The highest PER values was observed in fishes fed 45% protein-based feed (0.65) followed by 50% (0.56), 40% (0.38) and35% (0.17). The food conversion ratio was lowest for 45% protein diet (3.41), while the greatest for 35% protein feed (16.85). It was concluded that a 45% protein-based diet was the best feed formulation for higher production of Tor putitora. However, research on the same percentage of protein diet is recommended for yearlings.

This study aimed to evaluate the effect of replacing fish meal in the fish diet by zooplankton meal on the growth performance of European sea bass, Dicentrarchus labrax. A total of 900 fingerlings of the D. labrax were collected from fish hatchery Kilo 21, Alexandria and transported to the fish rearing unit in El-Max Research Station, National Institute of Oceanography and Fishers (NIOF), Alexandria, Egypt. After two weeks for acclimation, the fish were divided into 5 groups, 3 replicates for each group (60 fish in one cubic meter of Haba for each replicate). The five experimental diets were: G1: commercial diet (control group); G2, G3, G4, and G5 fish meal in this commercial diet was replaced by zooplankton meal as 25%, 50%, 75% and 100%, respectively. The highest values of growth performance parameters and PER & FER of D. labrax were recorded in G5, while the lowest values were recorded in the control group. The best average of FCR (1.75±0.02) was recorded for G5 and its bad average (2.18±0.18) was recorded in G1. The present study concluded that zooplankton positively affected growth performance parameters and enhanced feed utilization of sea bass. [ABSTRACT FROM AUTHOR]

An ontogenetic dietary shift is crucial for the survival and growth of piscivorous largemouth bass (LB). However, there is much to learn about the predator-prey interaction during the switching process. We carried out a series of indoor experiments to examine the predation capacity, predation preference, and growth performance of exotic juvenile LB feeding on candidate prey species in the Pearl River Delta. The widely distributed oriental river prawn (Macrobranchium nipponense), barcheek goby (Ctenogobius giurinus), western mosquitofish (Gambusia affinis), silver carp (Hypophthalmichthys molitrix), and mud carp (Cirrhinus molitorella), with relatively similar total lengths, were selected as potential prey based on their availability and habitat use. Our results show that predation capacity and preference varied quantitatively and qualitatively among prey species. The number of oriental river prawns killed was significantly less than that of fish species, comparing the 1st hour with the 24th hour (p < 0.01). The feeding rhythm of LB varied significantly from crayfish to fish. Numerically, Jacobs’ selection index reinforced LB’s special preference for predating G. affinis. Although there were obvious variations in predation capacity and feed selection, no statistically significant growth differences were detected among LB groups feeding on live M. nipponense, G. affinis, H. molitrix, and C. molitorella (p < 0.05). These findings suggest that the successful ontogenetic dietary shift of juvenile LB may depend on the availability and vulnerability of local fish species. Further study on the reproductive phenology of potential fish prey may help to predict LB’s establishment.

Influence of macrophytes on freshwater snail Pila globosa was examined both in the field and in the laboratory. Study of food utilization parameters on different sized Pila globosa when provided with different set of food highlighted that small sized Pila globosa prefer same type of food as indicated by higher absorption rate when fed with Eichhornia or Vallisneria only while medium sized snail prefer different types of food as absorption rate and absorption efficiency was more for medium sized snails when they were fed with Eichhornia alternatively with Vallineria. It means that growth of medium sized snail is good when diversity of aquatic macrophytes persist. Large sized snails too prefer different types of food but due to aberration of radula, they do not rasp effectively. The aberration of radula may be caused by ageing. The nutritional value of combination food is higher than single food as observed by food conversion ratio. Smaller snails have better food conversion efficiency in comparison to larger ones. For selection of types of macrophytes, Pila globosa were first studied under natural condition. Density, biomass, growth rate and net productivity were calculated. In the month of August 2017, the density (112/m²) and biomass (1129.2 gm/m²) was maximum while nil in the winter months of November and December 2017. Growth rate (15mg/day) and net daily productivity (731 mg/m²/day) was highest at spot 1 while negative growth rate (-2mg/day) and net daily productivity (-0.41 mg/m²/day) at spot 4. [ABSTRACT FROM AUTHOR]

Bu çalışma istavrit balığının Trachurus mediterraneus Steindachner, 1868 Doğu Karadeniz’de kafeslerde kültür potansiyeli üzerine yapılan ilk çalışmadır. Balıklar, ağ tuzaklarla doğadan yakalanmış ve doğrudan kafeslere transfer edilmiştir. Büyütme çalışması Ekim 2010 ile Ekim 2011 arasında yürütülmüştür. Ebatları 5x5x3 m olan kare kafes, birbirinden tamamen bağımsız eşit hacimli üç eşit küçük kafese 5x1,6x1.5 m bölünmüş ve her bir küçük kafese yaklaşık 1000’er adet balık stoklanmıştır. Balıklar ticari deniz levreği yemi ile doyuncaya kadar elle günde iki kez yemlenmiştir. Çalışmanın başında 12.20±0.97 cm ve 24.09±3.25 g olan ortalama boy ve ağırlık değerleri çalışma sonunda 19.61±1.47 cm ve 76.80±16.24 g’a n= 100 ulaşmıştır. Ortalama yem değerlendirme ve yaşama oranları sırasıyla 2.33±0.21 2.122.54 ve % 95.58-98.59 olarak hesaplanmıştır. Bu sonuçlara göre, deniz kafeslerinde istavrit balığının su sıcaklığının 12 °C’nin altına düştüğü kış ayları haricinde büyüyebildiği sonucuna varılmıştır

Aquaculture's success highly depends on a controlled rapid growth of organisms with minimal costs associated. Growth and welfare of reared organisms are affected by physical, chemical, and biological parameters. Following factors can be highlighted as crucial: density, pH, salinity, temperature, dissolved oxygen (DO), and nutrients (nitrogen, phosphorus, etc.). Relationship between fish density and oxygen's optimum levels is essential for designing the performance of each species. Furthermore, it is also necessary to study fish stress factors and physiological responses. Two rearing experiments with gilthead seabream (Sparus aurata) were performed, in order to test different densities (5, 10 and 20 kg/m3) for 9 weeks (271 ± 1.9 g) and to test different levels of oxygen (40%–60%, 60%–80%, and 80%–100%) for 6 weeks (316.3 ± 1.73 g). In both experiments, physiology and growth parameters were analysed, as well as water quality. This study showed that no relation was observed between density and fish physiology, but there structural (gill lesions) and physiological changes (haematocrit) were observed for seabream reared at low levels of DO. [ABSTRACT FROM AUTHOR]

The goal of this study was to compare the growth performance of growing/finishing pigs housed in a hoop barn system and in traditional confinement. A total of twenty Bísaro breed pigs, with 98.6±5.71 days of age, and 25.4±4.87 kg of BW were used (beginning of experiment). The pigs were equally distributed in two groups: Gr1 - hoop barn (3.0 m2/pig) with outdoor access (200 m2/pig); and Gr2 - traditional confinement with straw bedding (1.8 m2/pig). Both groups were fed with the same diet. During the next 98 days' period (growing phase) and until pigs reached approximately 80 kg LW, the animals were fed with a concentrate diet. In the finishing phase consisting of a final 70 days period until slaughter, the animals reached between 110-120 kg LW and were fed with concentrate and cornflour. The feed intake per group was registered daily and growth performances were collected every two weeks. During the growing phase no differences (P > 0.05) were observed in the average daily gain (ADG) between Gr1 (0.546±0.10 kg/day) and Gr2 (0.563±0.05 kg/day). However, a higher variability was observed in hoop barn group (CV of 18.1% vs. 8.8% in confinement). Similar results were observed during the finishing phase with ADG of 0.535±0.09 kg for Gr1 and 0.505±0.07 kg for Gr2 (P > 0.05). In both growing and finishing phases, the feed conversion rates (FCR) were 3.11 on the Gr1 versus 3.12 kg/kg on the Gr2, and 3.44 in Gr1 versus 3.53 in Gr2, respectively. Despite the different housing systems, ADG and FCR per period were identical in both systems. To the consumer's point of view, the positive aspects of the hoop barn system, such as the use of uncultivated land, product image and pig welfare, are sustainably attractive and therefore could be further reflected in the market. El objetivo de este estudio fue evaluar el crecimiento de cerdos alojados en un sistema hoop barn, en comparación con el confinamiento tradicional. Veinte cerdos de raza Bísaro, con 98,6±5,71 días de edad y 25,4±4,87 kg de peso vivo, se distribuyeron aleatoriamente en dos grupos: Gr1 - hoop barn (3,0 m2/cerdo) con acceso al exterior (200 m2/cerdo); Gr2 - confinamiento tradicional con cama de paja (1,8 m2/cerdo). La dieta fue igual para ambos grupos. Durante la fase de crecimiento (98 días) y hasta 80 kg de peso vivo, los animales fueron sometidos a una dieta con concentrado. A continuación, durante 70 días y hasta el sacrificio (110-120 kg de peso vivo), también estaba disponible harina de maiz. La ingesta de alimento por grupo se registró diariamente y los pesos vivos individuales se recogieron por quincena. La ganancia media diaria (ADG) durante la fase de crecimiento fue de 0,546±0,10 kg (Gr1) y 0,563±0,05 kg (Gr2) sin diferencias significativas (P> 0,05), pero con mayor variabilidad en el sistema hoop barn (CV de 18,1% vs. 8,8% de confinamiento). En la fase de acabado, el ADG fue 0,535±0,09 kg (Gr1) y 0,505±0,07 kg (Gr2) (P> 0,05). La eficiencia de conversación alimenticia (FCR) en las fases de crecimiento y de acabado fue de 3,11 kg/kg (Gr1) y 3,12 kg/kg (Gr2) y 3,44 (Gr1) y 3,53 (Gr2), respectivamente. A pesar de las diferencias en el alojamiento, la ADG y el FCR fueron idénticos en ambos sistemas de producción. Para el consumidor, las ganancias asociadas con el sistema hoop barn, como el uso de tierras no cultivadas, el bienestar del cerdo y la imagen del producto, son atractivas y por lo tanto, esto se reflejará en el mercado. [ABSTRACT FROM AUTHOR]

This experiment was conducted at the poultry farm of Animal Production Department - College of Agriculture - University of Baghdad, for the period from 18/9/2016 t0 30/10/2016. The aim of this experiment was to investigate the effect of adding different levels of β- Mannanase (0، 0,025 ، 0,05 ، 0,075 ، 0,1 ، 0,125%) to the diets on productive traits of broiler chickens, A total of 450 unsexed Ross 308, one day old was used in this experiment. chicks were fed on starter for 1_ 10 diet the day of age and on Grower diet for 11_ 24 the days of age the birds and finisher diet for 25 _ 42 days of the birds age, Birds were distributed on six treatments: T 1 as control group (without any addition) however T2, T3, T4, T5, and T6, were supplemented with β_Mannanase in the diet concentrations (0، 0,025، 0,05، 0,075، 0,1، 0,125%) respectively, The results indicated that the addition of β_Mannanase in the diet which concentration (0.05 %) (T3) led to significant improvement in live body weight and average body weight gain of the birds. [ABSTRACT FROM AUTHOR]

This study was carried out at Poultry Research Station, State Board of Agricultural Research, Ministry of Agriculture for the period from 27 September 2014 to 9 November 2014 to evaluate the Supplementation of different levels of Conjugated Linoleic Acid (CLA) on productive performance of broiler. Four hundred eighty chicks (Ross-308),one day old were randomly distributed to four dietary treatments for 42 days of age with 3 replicates/vtreatment (40 bird/replicate). Experimental treatments were as follow; T1 (Control diet) without supplement, while the treatment T2, T3 and T4 were Supplemented with 1, 1.5, 2 g CLA /kg diet respectively. The results showed significant (P ≤ 0.05) increased in mean of body weight, weight gain, average feed consumption and the feed conversion ratio, for the birds of treatments T3 and T4 in comparison with control treatment (T1). A significant (P ≤ 0.05) improvement was found in dressing percentage of treatments T3 and T4 in comparison with control treatment, whilst the breast percentage was significantly higher in all treatments which supplemented CLA than T1 treatment. The liver percentage weight has significantly (P ≤ 0.05) increased whereas the abdominal fat percentage has significantly (P ≤ 0.05) decreased in treatment T4 in comparison with control treatment. It is concluded that CLA supplementation at levels 1.5 and 2 g/kg diet of broiler chicken has improved productive performance. [ABSTRACT FROM AUTHOR]

Objetivou-se neste estudo propor e discutir método de avaliação da eficiência de conversão do alimento em produto em bovinos de corte com base na utilização de técnicas de regressão. Os procedimentos matemáticos e estatísticos foram desenvolvidos a partir de banco de dados formado pela mensuração do consumo de matéria seca e do ganho médio diário em 380 bovinos zebuínos puros ou mestiços em 15 diferentes experimentos constantes na base de dados do sistema BR-CORTE. Foram propostas duas aproximações baseadas no ajustamento de modelos de regressão linear e não-linear, tendo o ganho médio diário como variável independente e o consumo de matéria seca como variável dependente. A utilização do alimento pelo animal foi estratificada em demanda para mantença e eficiência real de conversão em produto. O parâmetro demanda para mantença possui interpretação similar em ambas as aproximações. Na solução linear, assume-se que a eficiência real de conversão em produto seja fixa e independente do ganho médio diário. Por outro lado, na solução não-linear, assume-se que a eficiência real de conversão em produto seja variável e dependente do ganho. O critério de informação de Akaike foi proposto como ferramenta para escolha entre os modelos linear e não-linear. A avaliação da eficiência de transformação do alimento em produto em bovinos de corte por meio de técnicas de regressão possibilita o entendimento mais amplo da eficiência de uso do alimento em sistemas de produção, pois permite estratificar as demandas em mantença e produção. Muitos inconvenientes associados ao uso de índices baseados em razões, como a conversão alimentar, são eliminados, ampliando a acurácia e a precisão das inferências nutricionais.The objective of this study was to propose and discuss a method to evaluate the efficiency of feed conversion into product from beef cattle based on regression techniques. The mathematical and statistical procedures were developed using a database composed of measurements of dry matter intake and average daily gain of 380 pure or crossbred zebu animals in 15 different experiments in the database from the BR-CORTE nutritional system. Two approaches were presented, based on linear and non-linear regression, with average daily gain and dry matter intake used as independent and dependent variables, respectively. The feed utilization by the animal was stratified into maintenance demand and real efficiency of conversion into product. The maintenance demand presents similar interpretation in both approaches. When linear solution is considered, the real efficiency of product conversion is assumed to be steady and independent on average daily gain. On the other hand, when the non-linear solution is adopted, the real efficiency of product conversion is assumed to be variable and dependent on gain. Alaike information criterion was proposed to decide which model suits best. The evaluation of the efficiency of transformation of feed into product, in beef cattle, by regression techniques allows a broader understanding of system efficiency for it enables stratification of maintenance and production demands. Several inconvenient aspects concerning ratio indexes, such as food conversion ratio, are avoided and the nutritional inferences become more accurate and precise.

Effects of stocking density on growth, food conversion ratio, specific growth rate, percentage of body weight increase in Huso huso were studied in two phases. Juveniles below one year old with an average weight of 92.09±1.72 grams and stocking densities of 1.6, 2.8 and 4 kg/m2 in 3 replicates for 100 days were reared as the phase one group. One year old Huso huso with an average weight of 918.13±21.87 grams and stocking densities of 1.5, 2.5, 3.5 and 4.5 kg/m2 reared for 120 days in 2000 liter fiberglass tanks were the second phase. Results revealed negative impact of density on growth, percentage of body weight, and specific growth rate and food conversion ratio in both phases. In the first phase, lower stocking density (1.6 kg/m2) showed significant increase in growth rate (P

This study is the first potential culture of the Mediterranean horse mackerel (Trachurus mediterraneus Steindachner, 1868) in cages in the Southeastern Black Sea. The wild fish was captured by net and transferred into sea cages. Growth study was performed between October 2010 and October 2011. Sea cage which 5x5x3 m dimensioned, was divided there equal volume (5x1, 6x1.5 m) independent from the other, and the fish of approx. 1000 specimen was stocked in per volume. Commercial seabass feed was used, and ad libitum feeding regime was set as twice a day. At the beginning, the experimental fish were 12.20±0.97 cm in length and 24.09±3.25 g in weight, and at the end of study, they reached to 19.61±1.47 (n= 100) cm in length and 76.80±16.24 g in weight. Average feed conversion ratio and the survival rate were calculated as 2.33±0.21 (2.12 to 2.54), and 95.58-98.59%, respectively. According to the results of this study, there is a potential for culturing horse mackerel in sea cages and fish grow trough out the year except winter when water temperature decreased to the 12 °C. [ABSTRACT FROM AUTHOR]

Juvenile Huso huso with average weight of 28.76±0.35were reared in fiberglass tanks and earthen ponds for 29 weeks in order to examine potential of rearing of the fish for meat production purposes. Fish in fiberglass tanks showed weight increase up to 584.17 grams in 200 days and produced 6 kg of biomass per litre. Survival ratio, food conversion ratio and specific growth rate were measured as 98.4%, 2.21 and 1.41 (% per day) for the fish respectively. During the experiment period, H. huso reared in the earthen ponds reached a weight of 708 grams and produced 1.5 kg of biomass per litre. The survival rate, food conversion ratio and specific growth rate for the fish cultured in the earthen ponds were 85.7%, and 1.32 and 1.69 (% per day). Based on the results, the fiberglass tanks provided better growth condition in the beginning of the experiment. However, in later stages of rearing the trend was reversed and fish reared in earthen ponds showed more suitable condition although no statistically significant differences between treatments were found (p>0.05). Growth pattern of fish was highly influenced by rearing condition (p

Abstract: Populations of a rheophilic cyprinid Barbus barbus have declined in last decades, which created a need of conservation aquaculture. Production of stocking material in controlled conditions calls for optimization of the two major factors, temperature and diet. Condition, growth and food conversion ratio in fish fed a formulated diet Aller Futura were compared with those on natural food—frozen Chironomidae larvae at 17, 21 and 25°C. Groups of 60 early juveniles (0.6–3.7g) were reared in each of 18 aquaria in which six experimental groups were run in triplicate. Daily food ratios were adjusted according to fish biomass, differences in hydration between the two diets and rearing temperature. No mortality occurred during the experiment. Condition coefficient K was significantly higher in fish fed Aller Futura compared to those fed Chironomidae irrespective of temperature tested; body deformities were not recorded. Relative growth rate at the same temperature was always higher in fish on the formulated diet than in those fed Chironomidae, and food conversion ratio was always suppressed, both suggesting an efficient utilization of Aller Futura for growth in B. barbus early juveniles. On both diets the coefficient K was depressed at 21°C. Relative growth rate (RGR) was accelerated with temperature according the Krogh’s “normal curve” within the range 21–25°C, while at lower temperatures (17–21°C) the observed values of temperature coefficient Q 10 were much higher than the theoretical Q 10 values based on Krogh’s “normal curve”. Food conversion ratios (FCR) were reduced on both diets at 21 and 25°C. Theoretical optimum temperatures for food conversion were 22.0 and 23.6°C. Summing up, responses of three independent indices: condition, growth and food utilization locate the optimum temperature for B. barbus between 21 and 25°C. No evidence was found that the effect of temperature on these indices was substantially modified by the diet. [Copyright &y& Elsevier]

Juvenile Haliotis rufescens were reared in the laboratory in order to investigate the extent to which fresh kelp and formulated feeds with 250 g kg−1 (25P) and 380 g kg−1 protein content (38P) affected their growth rate, gut residence time (GRT), food consumption ( C), food conversion ratio (FCR) and digestibility. Abalone from 38P attained the highest growth rate (70.5 ± 4.2 μm day−1; 98.3 ± 6.95 μg day−1), followed by 25P (47.9 ± 2.79 μm day−1; 67.4 ± 2.82 μg day−1) and kelp (23.6 ± 3.36 μm day−1; 28.2 ± 4.11 μg day−1). No significant differences were observed in consumption rate among treatments (0.61–0.68% body weight per day), yet kelp-fed abalone exhibited higher FCR (2.44), protein efficiency ratio (4.42), and apparent digestibility of dry matter (69.5%), protein (69.8%) and gross energy (79.2%) than 38P organisms (59.8, 62.4 and 62.2%, respectively). They also showed longer GRT (23.1 ± 0.93 h). This study demonstrated that formulated diets with 250 g kg−1 and 380 g kg−1 protein inclusion can sustain higher growth rates of juvenile H. rufescens than fresh algae. These differences seem to be due to the amount of dietary protein. Kelp meal appears to improve the consumption and digestibility of balanced diets, and its inclusion in formulated diets is recommended. [ABSTRACT FROM AUTHOR]

The effects of different daily feeding rates on the specific growth rate and food conversion ratio of Siberian sturgeon (Acipenser baeri) were investigated in order to determine the optimum daily feeding rate for fish with an initial mean weight of 1736 ± 37 g. To this end, a Latin Square experimental set-up was designed consisting of four groups of 25 fish fed a rainbow trout diet at four different daily feeding rates (0.75, 1.00, 1.25 and 1.50% body weight/day) for four 2-week periods. Water temperature varied between 19 and 22 °C throughout the experiment. Mean specific growth rate and food conversion ratio values were found to be significantly different (P < 0.05) between the four treatments. The means of specific growth rate and food conversion ratio for fish fed at 0.75%, 1.00%, 1.25% and 1.50% body weight/day were computed as 0.47, 0.88, 0.89 and 0.64% day-1 and 1.71, 1.25, 1.40 and 2.43, respectively. At 19-22 °C the optimum daily feeding rate for Siberian sturgeon of 1736 g was determined to be 1.00% body weight/day. [ABSTRACT FROM AUTHOR]

Several studies have shown that food ration can affect the growth of cultured fish. Determining the optimal food ration would help to achieve better growth and also provide direct economic benefits due to reduced food wastage, which would lead to commercial success. Therefore, we studied the effects of ration levels on growth performance of 0+ juvenile yellowtail flounder to determine the optimal food ration. Two experiments were conducted; the first experiment as a preliminary using ration levels of 1%, 2%, 4%, 6% body weight per day (% bw day−1) held at 7.0 °C with a stocking density of 0.95 kg m−2 (∼45% bottom coverage). Results of this preliminary experiment indicated that fish fed with 1% bw day−1 had significantly lower growth (weight, length, body depth and specific growth rates (SGR)) than those fed with 2%, 4% and 6% ration. However, fish fed with rations of 1% and 2% showed significantly lower gross food conversion ratios (GFCR) than fish fed with 4% and 6% rations. Survival was not significantly affected by different ration levels. Based on these preliminary results, we used ration levels of 1%, 1.5%, 2% and 3% for the main experiment. Fish were held at 10 °C with a stocking density of 1.45 kg m−2 (∼34% bottom coverage). Results indicated that fish fed with 1%, 1.5% and 2% bw day−1 had significantly lower growth than fish fed with 3% bw day−1. GFCR was significantly different for all four rations. It was lower for 1% than 1.5%, 2% and 3% rations. Survival was not significantly different between any treatments. We discuss our results with emphasis on growth and economics (i.e., feed wastage) and stress the need to balance both components in a commercial operation. [Copyright &y& Elsevier]

A global population of already more than seven billion people has led to an increased demand for food and water, and especially the demand for meat. Moreover, the cost of feed used in animal production has also increased dramatically, which requires animal breeders to find alternatives to reduce feed consumption. Understanding the biology underlying feed efficiency (FE) allows for a better selection of feed-efficient animals. Non-coding RNAs (ncRNAs), especially micro RNAs (miRNAs) and long non-coding RNAs (lncRNAs), play important roles in the regulation of bio-logical processes and disease development. The functions of ncRNAs in the biology of FE have emerged as they participate in the regulation of many genes and pathways related to the major FE indicators, such as residual feed intake and feed conversion ratio. This review provides the state of the art studies related to the ncRNAs associated with FE in livestock species. The contribution of ncRNAs to FE in the liver, muscle, and adipose tissues were summarized. The research gap of the function of ncRNAs in key processes for improved FE, such as the nutrition, heat stress, and gut–brain axis, was examined. Finally, the potential uses of ncRNAs for the improvement of FE were discussed. [ABSTRACT FROM AUTHOR]

An ontogenetic dietary shift is crucial for the survival and growth of piscivorous largemouth bass (LB). However, there is much to learn about the predator-prey interaction during the switching process. We carried out a series of indoor experiments to examine the predation capacity, predation preference, and growth performance of exotic juvenile LB feeding on candidate prey species in the Pearl River Delta. The widely distributed oriental river prawn (Macrobranchium nipponense), barcheek goby (Ctenogobius giurinus), western mosquitofish (Gambusia affinis), silver carp (Hypophthalmichthys molitrix), and mud carp (Cirrhinus molitorella), with relatively similar total lengths, were selected as potential prey based on their availability and habitat use. Our results show that predation capacity and preference varied quantitatively and qualitatively among prey species. The number of oriental river prawns killed was significantly less than that of fish species, comparing the 1st hour with the 24th hour (p < 0.01). The feeding rhythm of LB varied significantly from crayfish to fish. Numerically, Jacobs' selection index reinforced LB's special preference for predating G. affinis. Although there were obvious variations in predation capacity and feed selection, no statistically significant growth differences were detected among LB groups feeding on live M. nipponense, G. affinis, H. molitrix, and C. molitorella (p < 0.05). These findings suggest that the successful ontogenetic dietary shift of juvenile LB may depend on the availability and vulnerability of local fish species. Further study on the reproductive phenology of potential fish prey may help to predict LB's establishment. [ABSTRACT FROM AUTHOR]

Feed efficiency and growth are the most important traits in pig production, and very few genetic markers have been reported to be associated with feed efficiency. The suppressor of cytokine signalling-2 (encoded by SOCS2) is the main negative regulator of somatic growth, and the knockout of SOCS2 and naturally mutant mice have high-growth phenotypes. Porcine SOCS2 was selected as a primary positional candidate for feed efficiency, because it is located on chromosome 5q, in the vicinity of a Quantitative Trait Locus (QTL) region for food conversion ratio in pigs. Here, we report five single nucleotide polymorphisms identified by sequencing of the promoter region and exon 1. One PCR-RFLP assay was designed for genotyping the polymorphism c.1667A > G (GenBank Accession No ). Association analyses were performed in an Australian mapping resource pedigree population (PRDC-US43) for food conversion ratio, backfat, IGF1 level and growth traits and showed significant effects on average daily gain on test (ADG2) ( P < 0.01) and marginal association with food conversion ratio (FCR) ( P < 0.08). [ABSTRACT FROM AUTHOR]