Effects of delaying post-hatch feeding on lipid peroxidation and antioxidant enzyme mRNA expression in the pectoralis major muscle of newly hatched chicks.

Excessive lipid peroxidation negatively affects the physiological response and meat quality of chickens. Delaying post-hatch feeding was previously found to increase lipid peroxidation in the skeletal muscle of finishing broiler chickens. The aims of this study were to investigate the effects of delayed post-hatch feeding on lipid peroxidation and the mRNA expressions of antioxidant enzymes in the pectoralis major muscle of broiler chicks during the post-hatching period. Newly hatched chicks either had immediate free access to feed (freely-fed chicks) or had no access to feed from 0 to 2 days old (delayed-fed chicks), after which both groups were fed ad libitum until 4 or 13 days old. The lipid peroxidation level was higher in the delayed-fed than freely-fed chicks at 2, 4, and 13 days old. At 2 days old, the mRNA expressions of Cu/Zn-SOD, Mn-SOD, and GPX7 were lower in the delayed-fed than freely-fed chicks, while catalase mRNA levels did not differ. Furthermore, at 4 and 13 days old, lower mRNA expressions of Cu/Zn-SOD and Mn-SOD were observed in the delayed-fed than freely-fed chicks. These results suggest that delaying post-hatch feeding reduces the mRNA levels of Cu/Zn-SOD and Mn-SOD, consequently affecting muscle lipid peroxidation in chicks during subsequent growth.

Habitat and community structure modulate fish interactions in a neotropical clearwater river

Species interactions can modulate the diversity and enhance the stability of biological communities in aquatic ecosystems. Despite previous efforts to describe fish interactions in tropical rivers, the role of habitat characteristics, community structure, and trophic traits over these interactions is still poorly understood. To investigate among-habitat variation in substratum feeding pressure and agonistic interactions between fishes, we used remote underwater videos in three habitats of a clearwater river in the Central Western, Brazil. We also performed visual surveys to estimate the abundance and biomass of fishes and proposed a trophic classification to understand how these variables can affect fish interactions. Community structure was the main factor affecting the variation in the interactions among the habitats. Biomass was the main variable determining which habitat a fish will feed on, while species abundance determined with how many other species it will interact in the agonistic interaction networks for each habitat. Specific habitats are not only occupied, but also used in distinct ways by the fish community. Overall, our results demonstrate the importance of the heterogeneity of habitats in tropical rivers for the interactions performed by the fishes and how the intensity of these interactions is affected by community structure.(AU)

Interações realizadas por peixes podem modular a diversidade e assegurar a estabilidade de comunidades em rios tropicais. Apesar dessa importância, poucos estudos relacionam as interações ecológicas com as características do habitat, estrutura da comunidade e atributos das espécies de peixes. Por meio de filmagens remotas subaquáticas nós verificamos como a pressão alimentar dos peixes sobre a comunidade bentônica e as interações agonísticas entre peixes são influenciadas por essas características do habitat e da comunidade em um rio tropical de água clara na região Centro-Oeste do Brasil. Também realizamos censos visuais para estimar a abundância e a biomassa dos peixes e propusemos uma classificação funcional para entender como essas variáveis podem afetar as interações dos peixes. A estrutura da comunidade foi o principal fator que afetou a variação nas interações entre os habitats. A biomassa dos peixes determinou em qual hábitat um peixe se alimentará, enquanto a abundância das espécies determinou com quantas outras espécies elas interagem nas redes de interações agonísticas de cada habitat. Habitats específicos não são apenas ocupados, mas também utilizados de maneiras distintas pela comunidade de peixes. Nossos resultados demonstram a importância da heterogeneidade de habitats para as interações realizadas pelos peixes em rios tropicais e como a intensidade dessas interações é afetada pela estrutura da comunidade.(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.

In ovo feeding of creatine pyruvate alters energy reserves, satellite cell mitotic activity and myogenic gene expression of breast muscle in embryos and neonatal broilers.

We investigated the effects of in ovo feeding (IOF) of creatine pyruvate (CrPyr) on energy reserves, satellite cell mitotic activity (SCMA) and myogenic gene expression in breast muscle of embryos and neonatal broilers. A total of 960 eggs were randomly allocated into three treatments: 1) non-injected control group, 2) saline group injected with 0.6 mL of physiological saline (0.75%), and 3) CrPyr group injected with 0.6 mL of physiological saline (0.75%) containing 12 mg CrPyr/egg at 17.5 d of incubation. After hatching, a total of 120 male chicks were randomly assigned to each treatment group, with eight replicate sets per group. Selected chicks had body BW close to the average of their pooled group. Our results showed that the total and relative breast muscle weights of broilers subjected to CrPyr treatment were higher than those in the control and saline groups on 19 d of incubation (19 E), the day of hatch, 3 and 7 d post-hatch (P < 0.05). The myofiber diameter and cross-sectional area of individuals in the CrPyr group were higher than those in other treatments on 3 and 7 d post-hatch (P < 0.05). Moreover, IOF of CrPyr increased (P < 0.05) creatine concentrations on 19 E, the day of hatch and 3 d post-hatch, the same treatment increased phosphocreatine concentrations on 19 E. Broilers in the CrPyr group showed higher expression of myogenic differentiation 1 (MyoD) (P < 0.05), myogenin and paired box 7 (Pax7), as well as higher index of SCMA on 3 d post-hatch. However, myostatin mRNA expression in CrPyr-treated broilers was down-regulated on 3 d post-hatch (P < 0.05). These results indicated that IOF of CrPyr increased energy reserves of embryos and SCMA of broilers on 3 d post-hatch, which led to enhanced muscle growth in the late embryos and neonatal broilers. Additionally, IOF of CrPyr increased the activity of satellite cells possibly through up-regulating MyoD, myogenin, and Pax7 mRNA expression and down-regulating myostatin mRNA expression.

Padrões de deslocamento de bezerras de corte recebendo suplemento em pastagem de azevém / Displacement patterns of beef heifers receiving supplement in Italian ryegrass pasture

O objetivo deste trabalho foi avaliar o tempo de permanência, o número de bocados nas estações e o deslocamento entre estações alimentares por bezerras de corte em pastagem de azevém (Lolium multiflorum Lam.) e recebendo farelo de arroz integral como suplemento em três níveis (0,0; 0,5 e 1,0% PC). O método de pastejo foi rotacionado, com número variável de animais. O período de descanso foi estabelecido pela soma térmica (ST) de 187,5ºC, equivalente à ST necessária para a emissão de 1,5 folhas de azevém. O delineamento experimental foi inteiramente ao acaso, com medidas repetidas no tempo, três níveis de suplemento e seis ciclos de pastejo. O tempo de permanência em cada estação alimentar (9,4s) foi semelhante para bezerras exclusivamente a pasto e as que receberam 1,0% PC de suplemento. As bezerras que receberam 0,5% PC de suplemento permanecem 1,1s a mais na estação alimentar quando comparadas com as bezerras nos demais níveis. O deslocamento entre estações alimentares (1,7 passos) e o número de bocados em cada estação alimentar (sete bocados) foram semelhantes independentemente do nível de farelo de arroz fornecido. As bezerras, ao receberem 0,5% PC de farelo de arroz, são mais dependentes da presença de lâminas foliares no estrato pastejável do dossel.(AU)

The aim of this study was to evaluate the length of stay and number of bites in the feeding stations and displacement between feeding stations for beef heifers on ryegrass pasture (Lolium multiflorum Lam.) and receiving rice bran as a supplement in three levels (0.0; 0.5 and 1.0% BW). The grazing method was rotational with variable number of animals. The interval between grazing was set by the thermal sum (TS) of 187.5ºC equivalent to TS necessary for externalization of 1.5 leaf lamina of ryegrass. The experimental design was completely randomized with repeated measures on time, three levels of supplement and six grazing periods. The stay time at each feeding station (9.4 sec.) was similar for heifers exclusively on pasture and receiving 1.0% supplement BW. Heifers that received 0.5% supplement BW remained 1.1 sec. longer at the feeding station than heifers on other supplement levels. Displacement between feeding stations (1.7 steps) and the number of bites in each feeding station (7 bites) were similar regardless of the supplied rice bran level. Heifers receiving 0.5% rice bran BW are more dependent on the presence of leaf blades in grazeable stratum of canopy.(AU)

Effect of feeding frequency on growth, body composition, antioxidant status and mRNA expression of immunodependent genes before or after ammonia-N stress in juvenile oriental river prawn, Macrobrachium nipponense.

Feeding frequency is important for the improvement of growth performance and immunity of aquatic animals. In this study, the effect of feeding frequency on growth, body composition, antioxidant status and mRNA expression of immunodependent genes before or after ammonia-N stress was examined in Macrobrachium nipponense. Prawns were randomly assigned to one of five feeding frequencies (1, 2, 3, 4 and 6 times/day) following the same ration size over an 8-week growth trial. After the feeding trial, prawns were challenged by ammonia-N. The weight gain of prawns fed with 3-6 times/day was significantly higher than that of prawns fed with 1 time/day. The best feed conversion ratio was obtained from prawns fed with 3-6 times/day. Body crude lipid with feeding frequency of 3, 4 or 6 times/day was quite lower than that with 1 time/day. High feeding frequency (6 times/day) induced significantly elevated hepatopancreas super oxide dismutase and catalase activities. The malondialdehyde level in prawns fed with 6 times/day was also significantly increased, which was higher than that of prawns fed with other feeding frequency. mRNA expression of toll like receptor 3 and myeloid differentiation primary response protein MyD88 was promoted by feeding frequency from 3 to 4 time/day but inhibited by high or low feeding frequency. Similar mRNA expression variation trends of the two genes were observed in prawns after ammonia-N stress. After ammonia-N challenge, the highest cumulative mortality was observed in prawns fed with 6 times/day, which was significantly higher than that of prawns fed with 2-4 times/day. These findings demonstrate that (1) too high feeding frequency induced oxidative stress and malondialdehyde accumulation, negatively affecting the health status of prawns and reduced its resistance to ammonia-N stress; (2) the optimal feeding frequency to improve growth and immune response of this species at juvenile stage is 3-4 times/day; (3) considering costs of labour, a feeding frequency of 3 times/day is recommended for this prawn.

Toward improved postpartum cyclicity of primiparous dairy cows: Effects of genetic merit for production traits under contrasting feeding systems.

Milk genetic merit is known to affect commencement of luteal activity (C-LA) in dairy cows. This effect is considered to be due to energy exported in milk production. The present study aimed to identify and quantify the effects of genetic characteristics [breed and estimated breeding value (EBV) for milk yield and fat and protein contents] and feeding system on C-LA of primiparous cows. From 2006 to 2013, an experiment was conducted on 97 primiparous dairy (Holstein) and 97 primiparous dual-purpose (Normande) cows. Within breed, cows were classified into 2 groups: cows with high EBV for milk yield were included in a "milk group" and those with high EBV for fat and protein contents were included in a "content group." Within breed, exported energy in milk and body weight (BW) loss were similar for both genetic groups. Two grazing-based strategies were used, a high feeding system (maize silage in winter and grazing plus concentrate) and a low feeding system (grass silage in winter and grazing with no concentrate). Interval from calving to C-LA was studied performing survival analyses. Milk progesterone profile, milk yield, and body condition were analyzed using χ(2)-test and analysis of covariance. Holstein cows produced more milk (+1,810 kg in the high feeding system and +1,120 kg in the low feeding system) and lost more BW from wk 1 to 14 of lactation (-1.4 kg/wk) than Normande cows, whereas Normande cows had earlier C-LA than Holstein cows. Within breed, cows in the content group had earlier C-LA (associated hazard ratio=2.0) than cows in the milk group. Body weight at calving and loss from wk 1 to 14 of lactation tended to be associated with later C-LA. Cows in the high feeding system produced more milk (+2,040 kg for the Holstein cows and +1,350 kg for Normande cows) and lost less BW from wk 1 to 14 of lactation (+3.8 kg/wk) than cows in the low feeding system. No effect of feeding system or milk yield was observed on C-LA. Prolonged luteal phases were frequent (18% of cows) and were not associated with either breed or genetic group. Ovarian cycles were longer for Holstein than for Normande cows (+1.7d) because of a longer luteal phase and a longer interluteal interval. Results of the study could be useful to establish strategies to manage declining reproductive performances at genetic and environmental levels. This study showed that cows with a genetic predisposition to export milk energy through fat and protein contents had earlier C-LA than predisposed to export milk energy through yield.

Creep-feeding to stimulate metabolic imprinting in nursing beef heifers: impacts on heifer growth, reproductive and physiological variables.

This experiment compared growth, physiological, and reproductive responses of beef heifers with (MI) or without (CON) access to a creep-feeder, as a manner to stimulate metabolic imprinting while nursing their dams. On day 0, 60 Angus × Hereford heifers were ranked by BW and age (140 ± 3 kg and 68±3 days), and assigned to pairs so all ranking criteria were similar between heifers within each pair. On day 1, pairs were randomly assigned to MI (n=15) or CON (n=15). From day 1 to 51, MI pairs and their dams were allocated to 15 drylot pens where heifers had ad libitum access to a corn-based supplement through a creep-feeder. The CON pairs and their dams were maintained in an adjacent single drylot pen. From day 52 to 111, treatments were managed as a single group on a semiarid range pasture. On day 111, heifers were weaned and allocated to two pastures (one pasture/treatment), receiving hay and a corn-based concentrate until day 326. Heifer BW was recorded before and at the end of the creep-feeding period (day 1 to 51), and on days 112 and 326. On days 0, 51, 111, 187, 261, and 325, jugular blood was collected and real-time ultrasonography for longissimus muscle depth and backfat thickness assessment was performed. Blood was also collected every 10 days from days 113 to 323 for puberty evaluation via plasma progesterone. Liver and subcutaneous fat biopsies were performed on days 51, 111, 261 and 325. Average daily gain was greater (P<0.01) for MI than CON from day 1 to 51, tended (P=0.09) to be greater for CON than MI from day 112 to 326, while BW on day 326 was similar between treatments. On day 51, MI had greater (P ⩽ 0.01) plasma IGF-I and glucose concentrations, as well as mRNA expression of hepatic pyruvate carboxylase and adipose fatty acid synthase than CON. On days 261 and 325, plasma insulin concentrations were greater (P ⩽ 0.03) in CON than MI. Mean mRNA expression of hepatic IGF-I and adipose peroxisome proliferator-activated receptor gamma were greater (P ⩽ 0.05) in MI than CON. No treatment effects were detected for puberty attainment rate. In conclusion, supplementing nursing heifers via creep-feeding for 50 days altered physiological and biochemical variables suggestive of a metabolic imprinting effect, but did not hasten their puberty attainment.

Predictive factors of species composition of follower fishes in nuclear-follower feeding associations: a snapshot study

We tested whether habitat, identity, size of nuclear fishes, and intensity of bottom disturbance caused by their foraging can predict the composition of fish followers in nuclear-follower feeding associations. The study was carried out in a stream of the Serra da Bodoquena, Mato Grosso do Sul State, Southwestern Brazil. We performed underwater observational sessions (total 12 h) of such interspecific interactions to obtain data about the identity and abundance of the followers in the association, as well as the identity and size of the nuclear fish. We also evaluated whether different intensities of bottom disturbance due to the nuclear fish foraging and type of habitat may influence interactions. We recorded 38 episodes involving nuclear and follower species. Using a multivariate analysis with distance matrices, we noted that the intensity of bottom disturbance caused by nuclear fishes was the main predictor of the composition of the follower species (r = 0.55, p < 0.01), as well as the identity of the nuclear species, although this latter relation was weak (r = 0.09, p = 0.05). Such results indicate that followers react readily to sediment suspension, which reflects the trophic plasticity and opportunistic foraging characteristic of most tropical freshwater fishes.

Neste estudo testamos se o hábitat, a identidade e o tamanho da espécie nuclear, bem como a intensidade do distúrbio causado pela atividade do nuclear podem predizer a composição de seguidores na associação alimentar do tipo nuclear-seguidor. O estudo foi conduzido em um riacho da Serra da Bodoquena, estado do Mato Grosso do Sul, bacia do alto Rio Paraguai. Foram realizadas sessões de observação subaquática (totalizando 12 h), visando a obter informações sobre identidade e abundância dos seguidores, assim como identidade e tamanho da espécie nuclear, hábitat e intensidade do distúrbio causado pela atividade de forrageamento da espécie nuclear. Foram registradas 38 associações envolvendo cinco espécies nucleares e nove espécies seguidoras. A análise multivariada com matrizes de distância demonstrou que a intensidade do distúrbio causado pelos nucleares foi o principal preditor da composição de seguidores (r = 0,55, p < 0,01), assim como a identidade da espécie nuclear, embora essa relação tenha sido fraca (r = 0,09, p = 0,05). Esses resultados indicam que os seguidores respondem prontamente à suspensão de sedimento, refletindo a plasticidade trófica e o oportunismo de forrageio característico da maioria dos peixes tropicais de água doce.

Medical treatment of 145 cases of gastric dilatation in rabbits.

Gastric dilatation is an acute and life-threatening condition in pet rabbits commonly caused by an intestinal obstruction with pellets of compressed hair. Surgery is normally considered to be the treatment of choice to alleviate the obstruction. However, for various reasons such as restrictions by the owner, a high anaesthetic risk due to the critical condition of the patient or concurrent diseases, surgical treatment may be impossible. In a three-year period, 145 cases of gastric dilatation were treated medically with a combination of metoclopramide, metamizole, balanced fluid electrolyte solution with glucose and syringe feeding. No gender or breed predisposition could be noted. Four animals were euthanased, three of them directly after diagnosis. Eleven animals died, eight of them on the day of presentation. The medical treatment was successful in 130 cases (89 per cent) with a mean treatment time of three days. The animals were released from hospital when eating and defecating normally. Although the use of medical treatment of gastric dilatation has to be thoroughly considered, especially regarding the severity of obstruction, the painfulness and the animal's welfare, the good survival rate observed with these animals makes it a good option for all cases where surgical treatment is contraindicated.

Nutritional and physical characteristics of commercial hand-feeding formulas for parrots.

Hand-rearing is a common practice for the propagation of captive psittacines, however, research on their nutrition is limited and the requirements of growing chicks are not well understood. The nutrition of 15 commercially available parrot hand-feeding formulas was compared with the average content of the crops of free living Scarlet Macaw (Ara macao) chicks, as well as with the requirements of 6- to 12-week-old leghorn chickens. When the formulas were prepared for a 1-week-old chick, all except three maintained >90% of solids in suspension after 15 min and >60 after 30 min. On average the formulas had a similar metabolizable energy density as wild macaw crop samples. The concentration of crude protein in the formulas was higher than that of the crop sample average, while the crude fat was lower than the average crop samples. More than 50% of the formulas had concentrations of K, Mg, and Mn less than the crop sample average, and Ca and Na concentrations below the requirements established for 6- to 12-week-old leghorn chickens. For >45% of the formulas the concentrations of arginine, leucine, and methionine + cystine were below the requirements of 6- to 12-week leghorns. When commercial formulas were prepared according to the manufacturer's instructions, the different dilutions greatly magnified the nutritional differences among them. Overall, the inconsistency in the nutrient concentrations among the formulas suggests that there is no consensus among manufacturers of the correct nutrition for growing psittacines and the industry could benefit from continued research in this area.

Evaluation of the effect of accounting method, IPCC v. LCA, on grass-based and confinement dairy systems' greenhouse gas emissions.

Life cycle assessment (LCA) and the Intergovernmental Panel on Climate Change (IPCC) guideline methodology, which are the principal greenhouse gas (GHG) quantification methods, were evaluated in this study using a dairy farm GHG model. The model was applied to estimate GHG emissions from two contrasting dairy systems: a seasonal calving pasture-based dairy farm and a total confinement dairy system. Data used to quantify emissions from these systems originated from a research study carried out over a 1-year period in Ireland. The genetic merit of cows modelled was similar for both systems. Total mixed ration was fed in the Confinement system, whereas grazed grass was mainly fed in the grass-based system. GHG emissions from these systems were quantified per unit of product and area. The results of both methods showed that the dairy system that emitted the lowest GHG emissions per unit area did not necessarily emit the lowest GHG emissions possible for a given level of product. Consequently, a recommendation from this study is that GHG emissions be evaluated per unit of product given the growing affluent human population and increasing demand for dairy products. The IPCC and LCA methods ranked dairy systems' GHG emissions differently. For instance, the IPCC method quantified that the Confinement system reduced GHG emissions per unit of product by 8% compared with the grass-based system, but the LCA approach calculated that the Confinement system increased emissions by 16% when off-farm emissions associated with primary dairy production were included. Thus, GHG emissions should be quantified using approaches that quantify the total GHG emissions associated with the production system, so as to determine whether the dairy system was causing emissions displacement. The IPCC and LCA methods were also used in this study to simulate, through a dairy farm GHG model, what effect management changes within both production systems have on GHG emissions. The findings suggest that single changes have a small mitigating effect on GHG emissions (<5%), except for strategies used to control emissions from manure storage in the Confinement system (14% to 24%). However, when several management strategies were combined, GHG emissions per unit of product could be reduced significantly (15% to 30%). The LCA method was identified as the preferred approach to assess the effect of management changes on GHG emissions, but the analysis indicated that further standardisation of the approach is needed given the sensitivity of the approach to allocation decisions regarding milk and meat.

Influence of an active stable system on the behavior and body condition of Icelandic horses.

Horses are often stabled in individual boxes, a method that does not meet their natural needs and may cause psychical and musculoskeletal diseases. This problem is particularly evident in Iceland, where horses often spend the long winter periods in cramped boxes. The aim of this study was to analyze the suitability of a group housing system in Iceland, but the results are also applicable to horses of other regions. Eight Icelandic horses were observed in an active stable system, and their behavior and time budget were recorded. Movement and lying behavior were studied with ALT (Activity, Lying, Temperature detection) pedometers. The effect of an automatic concentrate feeding station (CFS) on the horses' behavior was examined. In the first period of investigation, the horses were fed concentrates manually, and in the second period, they were fed with the CFS. Additional behavioral observations and a determination of social hierarchy occurred directly or by video surveillance. The physical condition of the horses was recorded by body weight (BW) measurement and body condition scoring (BCS). The results showed a significant increase between the first and second trial periods in both the activity (P < 0.001) and the lying time (P = 0.003) of the horses with use of the CFS. However, there was no significant change in BW during the first period without the CFS (P = 0.884) or during the second period with the CFS (P = 0.540). The BCS of the horses was constant at a very good level during both trial periods, and the horses showed a low level of aggression, a firm social hierarchy and behavioral synchronization. This study concludes that group housing according to the active stable principle is a welfare-friendly option for keeping horses and is a suitable alternative to conventional individual boxes.

Diagnóstico y manejo de la obesidad en perros: una revisión / Diagnosis and management of obesity in dogs: a review / Diagnóstico e manejo da obesidade em cães: revisão

La obesidad es definida como la acumulación excesiva de grasa en el tejido adiposo del cuerpo, que se corresponde con un consumo inadecuado de energía y proteína lo que ocasiona un balance positivo de energía. El sobrepeso y la obesidad afectan a cerca del 25% de los perros, su presentación puede variar entre el 20 y 45% de la población canina que visita los centros y clínicas veterinarias de varios países occidentales y de Australia y, por lo tanto, se leconsidera una enfermedad nutricional común en los animales de compañía (perros y gatos). Los factores de riesgorelacionados con la obesidad incluyen la genética, la raza, la edad, la actividad física, el tipo de alimento consumidoy la castración, entre otros. El objetivo de esta revisión es realizar una aproximación al problema de la obesidadde los perros y gatos, sus factores de riesgo y su manejo integral, además de proponer un método sencillo paraestablecer la cantidad de alimento a suministrar a cada paciente de acuerdo con su estado fisiológico.

Obesity is defined as an excessive accumulation of fat in the adipose tissue of the body which results froman inappropriate consumption of energy and protein leading to a positive energy balance. Excess weight andobesity affect about 25% of dogs, a percentage that may vary between 20 and 45% of the dog populationpresenting for consultation in centers and veterinary clinics in several Western countries and Australia. Obesityis thus considered a nutritional disease common in companion animals (dogs and cats). Risk factors associatedwith obesity include genetics, breed, age, physical activity, the type of food consumed, and castration, amongstothers. This review intends to address the problem of obesity, its risk factors in dogs and cats and theircomprehensive management. Additionally, a simple procedure is proposed for establishing the precise quantity of daily food to be provided to each patient according to their physiological condition.

A obesidade é definida como acúmulo excessivo de gordura no tecido adiposo do corpo que resulta de um consumoinadequado de energia e proteína levando a um balanço energético positivo. O excesso de peso e a obesidade afetam cerca de 25% dos cães, sua apresentação pode variar entre 20 e 45% da população canina que visitam os centros eclínicas veterinárias em vários países ocidentais e na Austrália, por tanto, é considerada um desordem nutricionalcomum em animais de companhia (cães e gatos). Fatores de risco associados à obesidade incluem genética, raça,idade, atividade física, o tipo de alimento consumido, a castração, entre outros. O objetivo desta revisão é abordar o problema da obesidade em cães e gatos, seus fatores de risco e sua gestão integrada, além de propor um método simples para estabelecer a quantidade exata de alimento a ser oferecida para cada paciente de acordo com sua condição fisiológica.

Produção do híbrido "cachadia" em diferentes densidades de estocagem em sistema de recirculação de água / Production of cachadia hybrid at different densities in a recirculating aquaculture system

Avaliou-se o efeito da densidade de estocagem na produção de "cachadia" (Pseudoplatystoma fasciatum x Leiarius marmoratus) em sistema de recirculação de água. Nas duas primeiras fases, com duração de 27 e 40 dias e usando animais com média de peso inicial de 31 e 57g, respectivamente, foram testados 20, 40, 60 e 80 peixes/m³. Na terceira e quarta fase, usando peixes com média de peso de 169 e 399g durante 41 e 99 dias, respectivamente, foram testados 10, 20, 30 e 40 peixes/m³. A taxa de sobrevivência foi acima de 92 por cento, sem diferenças significativas entre tratamentos. Verificou-se redução no ganho de peso diário com redução com o incremento da densidade na segunda e na quarta fase experimental. A biomassa final apresentou relação direta com a densidade em todas as fases. Taxas de conversão alimentar entre 0,8 e 1,3:1 foram registradas. O "cachadia" atingiu 1,1kg em 207 dias de cultivo, mostrando-se promissor para a piscicultura intensiva.

The aim of this study was to investigate the effect of different stocking densities on cachadia production (Pseudoplatystoma fasciatum x Leiarius marmoratus) in recirculating aquaculture system. In the two first phases for 27 and 40 days using fish with average weight of 31 and 57g, respectively, densities 20, 40, 60, and 80 fish/m³ were tested. In the third and fourth trial, using fish with an average weight of 169 and 399g during 41 and 99 days, respectively, densities 10, 20, 30, and 40 fish/m³ were tested. Survival rate was higher than 92 percent, without stocking density differences between the treatments. Daily weight gain showed reduction with the increase of the density in the second and fourth trial. However, final biomass presented direct relationship with increase density in all trials. Feed conversion rates ranged 0.8 from 1.3:1 were registered. Cachadia hybrid reached 1.1kg in approximately seven months of rearing indicating promise for intensive production.

The influence of strain of Holstein-Friesian cow and feeding system on greenhouse gas emissions from pastoral dairy farms.

The purpose of this study was to model the effect of 3 divergent strains of Holstein-Friesian cows in 3 pasture-based feed systems on greenhouse gas (GHG) emissions. The 3 strains of Holstein-Friesian compared were high-production North American (HP), high-durability North American (HD), and New Zealand (NZ). The 3 feed systems were a high grass allowance system (MP, control); high stocking rate system (HS); and high concentrate supplementation system (HC). The MP system had an overall stocking rate of 2.47 cows/ha and received 325 kg of dry matter concentrate per cow in early lactation. The HS system had a similar concentrate input to the MP system, but had an overall stocking rate of 2.74 cows/ha. The HC system had a similar overall stocking rate to the MP system, but 1,445 kg of dry matter concentrate was offered per cow. A newly developed integrated economic-GHG farm model was used to evaluate the 9 milk production systems. The GHG model estimates on-farm (emissions arising within the farm's physical boundaries) and production system (incorporating all emissions associated with the production system up to the point milk leaves the farm gate) GHG emissions. Production system GHG emissions were always greater than on-farm emissions, and the ranking of the 9 systems was usually consistent under both methods. The exception was the NZ strain that achieved their lowest GHG emission per unit of product in the HC system when indirect emissions were excluded, but their lowest emission was in the HS system when indirect emissions were included. Generally, the results showed that as cow strain changed from lower (HD and NZ) to higher genetic potential (HP) for milk production, the GHG emission per kilogram of milk solids increased. This was because of a decline in cow fertility in the HP strain that resulted in a higher number of nonproductive animals, leading to a lower total farm milk solids production and an increase in emissions from nonproductive animals. The GHG emission per hectare increased for all strains moving from MP to HS to HC feed systems and this was associated with increases in herd total feed intake. The most profitable combination was the NZ strain in the HS system and this combination resulted in a 12% reduction in production system GHG emission per hectare compared with the NZ strain in the HC system, which produced the highest emissions. This demonstrates that grass-based systems can achieve high profitability and decreased GHG emissions simultaneously.

Effect of feed type and feeding frequency on macrophage functions in tilapia (Oreochromis niloticus L.).

In fresh water recirculation systems the type of feed and feeding frequency have a direct effect on water quality, growth, fish welfare and the response of the immune system. Four types of feed with different sources of plant protein (soybean concentrate, sunflower meal, corn gluten and pea) were provided at two feeding frequencies (two and eight times day(-1)) to observe effects on growth, cortisol levels and innate immunity (macrophage phagocytosis and respiratory burst) on tilapia in early stages of growth (2-10 g). Growth and cortisol parameters were quite similar among the groups of tilapia fed the different diets and frequencies at the end of the feeding period. Phagocytosis and respiratory burst were also very similar with the four feed types. However, macrophages from fish fed twice day(-1) were much less efficient in clearing bacteria after 24 h than the groups fed eight times day(-1). Our results suggest that an increased feeding frequency may confer a higher resistance to disease.

Milk conjugated linoleic acid response to fish oil and sunflower oil supplementation to dairy cows managed under two feeding systems.

Earlier research showed that conjugated linoleic acid (CLA) content in milk fat is highest when cows' diets are supplemented with a blend of fish oil (FO) and linoleic acid-rich oils. The objective of this study was to compare the effect of FO and sunflower oil (SFO) supplementation on milk cis-9, trans-11 CLA when dairy cows managed on pasture or in confinement. Fourteen Holstein cows were assigned into 2 treatment groups: cows grazed on alfalfa-grass pasture (PAS) or were fed corn silage-alfalfa hay mix ad libitum (LOT). Both groups were supplemented with a 8.2 kg/d grain supplement containing 640 g of FO and SFO (1:3 wt/ wt). Grain supplement was fed in 2 equal portions after each milking, for a period of 3 wk. Milk samples were collected during the last 3 d of the experimental period. Milk yield was greater with the LOT diet (23.1 kg/ d) compared with the PAS diet (19.4 kg/d). Milk fat percentages (2.51 and 2.95 for the LOT and PAS, respectively) and yields (0.57 and 0.51 kg/d) were similar for the 2 diets. Milk protein percentages were not affected by diets (3.34 and 3.35 for the LOT and PAS diets, respectively), but protein yields were lower for the PAS diet (0.61 kg/d) compared with the LOT diet (0.75 kg/ d). Treatment diets had no effect on milk trans C18:1 concentrations [10.64 and 9.82 g/100 g of total fatty acids (FA) for the LOT and PAS, respectively] or yields (60.65 and 64.01 g/d), but did affect isomers distributions. Concentration (g/100 g of total FA) of vaccenic acid was lower with the LOT diet (2.15) compared with the PAS diet (4.52), whereas concentration of trans-10 C18:1 was greater with the LOT diet (4.99) compared with the PAS diet (1.69). Milk cis-9, trans-11 CLA concentration was greater with the PAS diet (1.52) compared with the LOT diet (0.84). In conclusion, the increase in milk cis-9, trans-11 CLA content was greater when pasture-based diets were supplemented with FO and SFO. The lower cis-9, trans-11 CLA concentration in milk from the confinement-fed cows resulted from trans-10 C18:1 replacing vaccenic acid as the predominant trans C18:1 isomer.

A comparison of three strains of Holstein-Friesian cows grazed on pasture: growth, development, and puberty.

With the introduction of a protein milk payment system in New Zealand in 1988, there was an influx of North American (NA) Holstein-Friesian (HF) genetics into New Zealand (NZ) dairy herds, leading to an increase in the average percentage of NA genetics in NZ HF cows--from 2% in 1980 to 38% in 1999. Of interest has been the effect this change has had on farm profitability and on the management required for these animals, as well as the phenotypic changes that have occurred within the national herd under the breeding programs operated in NZ from 1970 to 1990. The objective of this study was to quantify differences in body dimensions, body weights, and puberty-related parameters among 3 strains of HF, representing animals of NZ origin representative of the genetics present in 1970 and 1990 and of NA origin with 1990s genetics. A total of 172 animals born in 1999 were compared. The strains were 1) NZ70, a strain of NZ Friesian (average 7% NA genetics) equivalent to high-genetic-merit (high Breeding Worth) cows farmed in the 1970s; 2) NZ90, a strain of HF of NZ origin (average 24% NA genetics) typical of the animals present in the 1990s; and 3) NA90, a strain of HF of NA origin (average of 91% NA genetics) typical of animals present in the 1990s. The differences in BW among all strains were significant at 6 and 12 mo of age. At 15 and 24 mo, the 2 NZ strains were significantly lighter than the NA90 animals. At 24 mo of age (i.e., prior to first calving), the NA90 strain animals (BW = 515 kg) were 22 and 34 kg heavier than the NZ90 and NZ70 strains. The body length of the NA90 strain was greater than either of the 2 NZ strains; the differences among the NA90 strain and the 2 NZ strains varied from 2 to 6 cm, with the differences generally being greater at older ages. The trend in heart girth difference among strains was similar to that observed for body length. The wither height of the NA90 animals was greater than that of the NZ strains by 1 to 7 cm, although there was no significant difference between the NA90 and NZ90 strains at birth. At puberty the NA90 heifers were 20 d older and 20 kg heavier than the NZ90 heifers, which in turn were 25 kg and 25 d older than the NZ70 heifers. The NA90 strain had a heavier mature body weight, and their older age at puberty suggested either that they mature later or that, under pastoral conditions, their growth rate is limited by their inability to consume sufficient metabolizable energy as grazed pasture, with a consequent delay in puberty. Results from this study will be useful in revising target BW in growing heifers of different germplasm.