Dietary electrolytes and thermal conditioning: minimizing heat stress in broilers

In tropical climates the heat is one of the major constraints to production of broilers and is responsible for inducing a high mortality, especially in the finishing phase. Thus, the objective of this study was to compare the thermal conditioning early (TC) and feed formulation using dietary electrolytes (DE). Therefore, the electrolyte balance of K+Na-Cl was set at 350 mEq/kg and electrolyte ratio (K+Cl)/Na) in the 3:1 program PPFR (http://www.fmva.unesp.br/ppfr). A total of 300 Cobb 500 1-dold male broiler chicks was randomly allocated to 24 floor pens with six replicates per treatment in a 2x2 factorial arrangement (with and without TC and with and without DE). Dietary treatments consisted: (T1) a traditional diet without TC; (T2) traditional diet with TC; (T3) with the application of dietary electrolyte and without TC and (T4) application of dietary electrolyte with TC. The thermal conditioning was conducted at 5 d of age (36°C for 24 h), only half of the batch (150 birds). After this period, all birds were transferred to boxes of 1.5 x3m (12 birds / box), with wood shavings reused as litter. Chicks were exposed to acute stress (36°C) for 8 h at the age 36, in all treatments, being electronically monitored the temperature and humidity of the microclimate of the birds. Feed and water were provided ad libitum, even during periods of stress. Were measured performance data (weight gain, feed intake and feed conversion) and mortality rate. The early thermal conditioning (T2) and effect of dietary electrolytes (T3) were effective to minimize the mortality of broilers subjected to acute heat stress with a significant difference (P<0.05), without prejudice on broiler performance. The results also showed that there was a more favorable effect when applied dietary electrolytes and thermal conditioning simultaneously (treatment T4). However, for the treatment none of these strategies has been applied (T1), the mortality rate was 83% over that in which they were applied (T4). It was concluded from this study that both techniques: the thermal conditioning early as the dietary electrolytes are efficacious in minimize the damaging effects caused by heat broiler.

Strategies to minimize heat stress in broilers chickens

The objective of this study was to evaluate the application of early age thermal conditioning (TC) and dietary electrolyte balances (DEB) to minimize the effect of heat stress. A total of 240 Cobb 500 1-d-old male broiler chicks was randomly allocated to 24 floor pens with six replicates per treatment in a 2x2 factorial arrangement (with and without TC and with and without DEB). Dietary treatments consisted: (T1) a traditional diet without TC; (T2) traditional diet with TC; (T3) with the application of dietary electrolyte and without TC and (T4) application of dietary electrolyte with TC. The thermal conditioning was conducted at 5 d of age (36°C for 24 h), only half of the batch (120 birds). After this period, all birds were transferred to boxes of 1.5 x 3m (10 birds / box), with wood shavings reused as litter. Chicks were exposed to chronic heat stress (32°C) for 6 h from 35 to 39 d of age, in all treatments, being electronically monitored the temperature and humidity of the microclimate of the birds. Feed and water were provided ad libitum, even during periods of stress. Were measured performance data (weight gain, feed intake and feed conversion) and mortality rate. Data were subjected to ANOVA using the GLM procedures of SAS. The results of this study demonstrated no interaction effects of all evaluated parameters (performance and mortality). Therefore, no synergism occurred when both strategies (TC and DEB) were applied. Only the first week there was prejudice on broiler performance with the application of the TC and apparently the technique of early age thermal conditioning no improve the resistance of broilers to chronic heat stress. On the other hand, DEB had significantly favorable effects (P<0.05) on performance and minimized mortality immediately after application of the TC.

Dietary electrolyte balance for broiler chickens under moderately high ambient temperatures and relative humidities

Cobb male broiler chicks (1,000) on new litter were used to evaluate effects of dietary electrolyte balance [DEB; Na+K-Cl, milliequivalents (mEq) per kilogram] under tropical summer conditions. Corn-soybean meal-based mash diets had salt (NaCl) alone or in combination with one or more supplements: sodium bicarbonate (NaHCO3), ammonium chloride (NH4Cl), or potassium bicarbonate (KHCO3). A completely randomized design, with five starter and grower feed treatments (control: 145, then 130 mEq/kg; or 0, 120, 240, or 360 mEq/kg throughout) and four replicate pens (1.5 x 3.2 m) per treatment (50 chicks per pen), was used. Diets were analyzed for Na, K, and Cl for confirmation. There were no significant (P < 0.05) effects of treatments on mortality or processing parameters. Water intake increased linearly with increasing DEB, giving higher litter moistures and lower rectal temperatures. Blood HCO3 and pH increased with the highest DEB (360 mEq/kg) causing respiratory alkalosis. The DEB of 240 mEg/kg gave best weight gain and feed conversion ratio, and ideal DEB predicted by regression analyses were 186 and 197 mEq/kg from 0 to 21 d of age and 236 and 207 mEq/kg of feed from 0 to 42 d, respectively. These DEB corresponded to estimated (interpolated) values in predicted optimal 186 to 197 mEq/kg starter of Na 0.38 to 0.40% and Cl 0.405 to 0.39% (K = 0.52%), in 207 to 236 mEq/kg starter, Na 0.409 to 0.445% and Cl 0.326 to 0.372% Cl (K = 0.52%), and in grower Na 0.41 to 0.445%, Cl 0.315 to 0.267% (K = 0.47%).

Dietary electrolyte balance for broiler chickens exposed to thermoneutral or heat-stress environments

Ross male broiler chicks (n = 480) on new litter were used in a randomized block design with two blocks (environmental rooms) and four treatments having four replicate pens (1.0 × 2.5 m; 15 chicks) each to evaluate dietary electrolyte balance (DEB; P < 0.05). Two rooms were 1) thermoneutral (Weeks 1 through 6, with decreasing maximum from 32 to 25°C and minimum from 28 to 19°C; relative humidity 49 to 58%) and 2) cyclic daily heat stress (Weeks 1 and 2, thermoneutral; Weeks 2 through 6, maximum temperatures 35, 35, 33, and 33°C, respectively; and minimum temperatures 23, 20, 19, and 19°C, respectively; relative humidity 51 to 54%). The DEB treatments (0, 140, 240, or 340 mEq Na + K - Cl/kg) had NaHCO3 plus NH4Cl, or KHCO3, or both added to corn-soybean meal mash basal diets with 0.30% salt (NaCl). In the thermoneutral room, DEB 240 increased 42-d weight gain and 44-d lymphocyte percentage and decreased heterophil percentage and heterophil to lymphocyte ratio compared to the DEB 40 treatment. The DEB 240 diets had 0.35 and 0.35% Na and 0.37% and 0.29% Cl in starter (0.75% K) and grower (0.67% K) diets, respectively. No DEB treatment differences were found in the heat stress room. For combined rooms, 42-d feed intake was higher for DEB 240 than for DEB 40. The 21-d weight gain was higher for DEB 240 than for DEB 40 or 140; and 21-d feed/gain was lower for DEB 40 than for DEB 340. The predicted maximum point of inflection for 21- and 42-d weight gains were DEB 250 and 201, with highest 42-d feed intake at 220.

Physiological responses of broiler chickens to heat stress and dietary electrolyte balance (sodium plus potassium minus chloride, milliequivalents per kilogram)

Individually caged male Cobb broilers (24), 44 d of age, were used to evaluate effects of heat stress (1 d of data collection) and dietary electrolyte balance (DEB; Na + K - Cl, mEq/kg from 1 d of age). During summer rearing, mortality was variable, but DEB 240 improved growth, feed conversion ratio, water intake, and waterrfeed ratio vs. DEB 0. The temperature sequence for heat stress was 24 to 32°C in 30 min, 32 to 36°C in 30 min, 36 to 37°C in 15 min, and 37 to 41°C in 45 min. Maximum temperature was held for 15, 60, 90, or 360 min for data collection (relative humidity averaged 42 ± 7%). Results from the same room before and after heat stress were analyzed by DEB (1-factor ANOVA) and before vs. after heat stress compared across DEB (2-sample t-test). Heat stress decreased blood Na, K, and pCO2, and lymphocytes but increased heterophils. Blood HCO3 rose, Cl declined, and hematocrit gave a concave pattern (lowest at DEB 120) as DEB increased. After heat stress, DEB O decreased blood Na and K, and DEB O and 120 levels decreased blood HCO3. After heat stress blood pCO2 and hemoglobin decreased with DEB 240, but it had highest pCO2, a key factor. The DEB 120 gave longest times to panting and prostration with DEB O and 240 results lower but similar statistically. In heat stress, DEB 360 was excessive, DEB 120 and 240 were favorable, and DEB 0 was intermediate based on hematology, panting, and prostration responses.

Chronic Diseases: Chronic Diseases and Development 2 Health, agricultural, and economic effects of adoption of healthy diet recommendations

Transition to diets that are high in saturated fat and sugar has caused a global public health concern as the pattern of food consumption is a mayor modifiable risk factor for chronic non-communicable diseases Although agri food systems are intimately associated with this transition, agriculture and health sectors are largely disconnected in their priorities policy, and analysis with neither side considering the complex inter relation between agri trade patterns of food consumption health, and development We show the importance of connection of these perspectives through estimation of the effect of adopting a healthy diet on population health, agricultural production trade the economy and livelihoods, with a computable general equilibrium approach on the basis of case studies from the UK and Brazil we suggest that benefits of a healthy diet policy will vary substantially between different populations, not only because of population dietary intake but also because of agricultural production trade and other economic factors

DIET of THE BLUE MARLIN (MAKAIRA NIGRICANS, LACEPEDE 1802) (PERCIFORMES: ISTIOPHORIDAE) of THE SOUTHWESTERN EQUATORIAL ATLANTIC OCEAN.

Diet composition of the blue marlin, Makaira nigricans, from the southwestern equatorial Atlantic Ocean was analyzed between October 2004 and November 2005. In the 226 stomachs of fish ranging between 100 and 311 cm lower jaw -fork length (LJFL), 44 items were identified, including 31 fishes and 13 cephalopods. Seventy stomachs were empty (23.6 %). M. nigricans fed preferentially on heavy and muscular scombrid fishes especially upon the skipjack tuna, Katsuwonus pelamis (Linnaeus, 1758), probably to sustain their high metabolism, and on a variety of other items composed mainly by epipelagic species of fish and cephalopods.

Co-feeding of live feed and inert diet from first-feeding affects Artemia lipid digestibility and retention in Senegalese sole (Solea senegalensis) larvae

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of six carbohydrate sources on dog diet digestibility and post-prandial glucose and insulin response

The effects of six extruded diets with different starch sources (cassava flour, brewer's rice, corn, sorghum, peas or lentils) on dog total tract apparent digestibility and glycemic and insulinemic response were investigated. The experiment was carried out on thirty-six dogs with six dogs per diet in a completely randomized design. The diets containing brewer's rice and cassava flour presented the greatest digestibility of dry matter, organic matter and gross energy (p < 0.05), followed by corn and sorghum; pea and lentil diets had the lowest. Starch digestibility was greater than 98% in all diets and was greater for brewer's rice and cassava flour than for lentils and peas diets (p < 0.05). Dogs' immediate post-prandial glucose and insulin responses (AUC <= 30 min) were greater for brewer's rice, corn, and cassava flour diets (p < 0.05), and later meal responses (AUC >= 30 min) were greater for sorghum, lentil and pea diets (p < 0.05). Variations in diet digestibility and post-prandial response can be explained by differences in chemical composition of each starch source including fibre content and starch granule structure. The nutritional particularities of each starch ingredient can be explored through diet formulations designed to modulate glycemic response. However, more studies are required to support these.

Effects of six carbohydrate sources on diet digestibility and postprandial glucose and insulin responses in cats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Métodos para estudo das respostas metabólicas de cães e gatos a diferentes alimentos

Durante o processo de assimilação e uso dos alimentos, diferentes respostas metabólicas podem ser desenvolvidas pelo organismo dos animais. Estas respostas são fruto da integração de mecanismos complexos, que envolvem os sistemas neuro-endócrino e o funcionamento dos órgãos, sendo influenciadas pela dieta, espécie animal, idade, condição fisiológica e composição corporal. Este trabalho enfoca a importância fisiológica e os métodos de estudo das respostas pós-prandiais aos carboidratos, bem como as alterações fisiológicas conseqüentes ao balanço eletrolítico da dieta. A quantidade, estrutura química e processamento industrial do amido determinam boa parte da resposta pós-prandial de glicose e insulina de cães. em gatos, outros mecanismos parecem ser mais importantes, como a ingestão de aminoácidos. A fibra alimentar também altera a resposta pós-prandial ao alimento, devendo ser consideradas sua quantidade, solubilidade e fermentabilidade no desenvolvimento das dietas. Os métodos de estudo destas respostas incluem avaliação das respostas glicêmica e insulínca pós-prandiais, teste endovenoso de tolerância à glicose e à arginina. O clâmp euglicêmico apresenta-se também como ferramenta de estudo, no entanto revela informações mais relacionadas ao animal do que à dieta. A compreensão do conjunto de alterações metabólicas aos carboidratos é importante no estudo do controle da saciedade, composição corporal e inúmeras doenças degenerativas e endócrinas. A concentração e relação entre os macro-elementos da dieta (Na, Cl, K, P, Ca, Mg e S) e dos aminoácidos sulfurados (metionina, cistina e taurina) interferem em inúmeras funções orgânicas, como a cardiovascular, neuromuscular, metabolismo ósseo, renal e pulmonar, refletindo-se no equilíbrio hidro-eletrolítico e ácido-básico orgânicos. de importância prática para cães e gatos encontram-se a relação destes nutrientes com cardiopatias, nefropatias, osteodistrofias e urolitíases. A relação entre os macro-elementos é estabelecida em mmol/kg de matéria seca da dieta, calculando-se seu balanço cátion-ânion (excesso de bases ou ânions dietéticos não determinados). Suas repostas orgânicas são medidas, dentre outros métodos, pela hemogasimetria, balanço hídrico, mensuração do volume dos espaços extracelular e vascular, supersaturação e pH urinários.

Exercise intensity, but not electrolyte reposition, alters plasmatic cortisol and glucose levels of horses submitted to 30 and 60km distance endurance rides

O presente estudo teve como objetivo comparar os níveis plasmáticos de glicose e cortisol de um grupo de eqüinos atletas submetidos ao esforço de longa duração (enduro eqüestre) em distâncias de 30 e 60km, com velocidades médias de 10 e 15km h-1, respectivamente. Os animais foram aleatoriamente separados em dois grupos, sendo que a um deles foi administrada, por via oral, uma pasta eletrolítica hipertônica antes, durante e após as referidas provas. O outro grupo foi usado como controle. Os resultados das concentrações de cortisol revelaram um aumento significativo, no primeiro momento, em que a intensidade do esforço era maior (15km/h), ou com a continuação deste (30km de distância), no segundo momento, para todos os grupos. Os resultados referentes à concentração de glicose permaneceram constantes durante a prova de 30km; entretanto, nos primeiros 20km da prova de 60km, tais resultados revelaram um aumento significativo no grupo controle, retornando a valores basais no momento subseqüente. A reposição eletrolítica tem a sua importância na manutenção do equilíbrio hidroeletrolítico e ácido básico e, no presente estudo, pode ter contribuído para a manutenção da concentração média de glicose plasmática.

Live and formulated diet evaluation through initial growth and survival of jundiá larvae, Rhamdia quelen

A larvicultura da maioria das espécies de peixes enfrenta o desafio da dependência do alimento vivo (AL) e da falta de dietas formuladas (DF) que atendam plenamente às necessidades das larvas. A baixa digestibilidade e a qualidade nutricional das DFs são alguns dos fatores que explicam o insucesso quando as larvas recebem apenas FD. Para avaliar o efeito da combinação da DF com o AL no crescimento e na sobrevivência de larvas de jundiá (Rhamdia quelen), comparando com o uso separado da DF ou do AL, larvas recém eclodidas (5,57 mm; 1,41 mg) foram estocadas inicialmente em 12 aquários de 10 L (100 larvas por aquário). Quatro réplicas foram alimentadas ad libitum com uma das três dietas por 20 (para DF) ou 48 dias (para AL ou a combinação DF + AL). As larvas alimentadas com apenas DF apresentaram crescimento e sobrevivência reduzidos quando comparadas àquelas alimentadas com AL ou a combinação DF + AL. Adicionalmente, as larvas do tratamento DF + AL apresentaram maior crescimento em peso (170 mg) que aquelas alimentadas apenas com AL (110 mg). O melhor desempenho das larvas alimentadas com DF + AL mostra que a maioria dos nutrientes exigidos pelas larvas é fornecida mais adequadamente quando ambas as dietas são fornecidas juntamente. Contudo, trabalhos sobre nutrição larval poderão contribuir ainda mais sobre a elucidação deste tema quando feitas comparações com o uso combinado de DF + AL, do que apenas testando isoladamente novos ingredientes e fontes protéicas normalmente utilizadas na elaboração de dietas para juvenis e adultos.

Does low-protein diet improve broiler performance under heat stress conditions?

Nutrition for broilers under high temperatures is extremely important for brazilian broiler chicken industry because the amounts of consumed nutrients and environmental temperature have great effects on bird performance and carcass quality. Among diet nutrients, protein has the highest heat increment; thus, during many years, diets with low protein level were recommended in order to reduce heat production in broiler chickens under heat stress. However, reports have shown that low-protein diets have negative effects on broiler performance when environmental temperature is high, because during heat stress, low food intake associated to a low diet protein induce amino acid deficiencies. Other studies have shown that broilers fed low-protein diets increase their energy requirement for maintenance with higher heat production. Thus, with the growth of broiler industry in tropical areas more challenges need to be faced by the farmers. So, both the ambient and nutritional conditions ought to be well managed to avoid negative effects on poultry production once they can affect the metabolism (body heat production under low temperature and body heat dissipation under high temperature) with consequence on poultry performance (meat and eggs).

Yeast extract and prebiotic in pre-initial phase diet for broiler chickens raised under different temperatures

Objetivou-se nesta pesquisa avaliar o desempenho, o rendimento de carcaça e a morfometria intestinal de frangos de corte criados em diferentes temperaturas e que receberam na fase pré-inicial ração contendo ou não extrato de leveduras e prebiótico. Foram utilizados 1.440 pintos machos de 1 dia de idade, criados em diferentes câmaras climáticas. As rações, acrescidas ou não de extrato de leveduras e prebiótico, foram oferecidas somente na fase pré-inicial (1 a 7 dias). A partir do oitavo dia, todas as aves receberam a mesma ração, reajustada de acordo com as recomendações usuais. Adotou-se o delineamento experimental inteiramente casualizado em arranjo fatorial 3 × 2 × 2, composto de três temperaturas de criação (calor, conforto e frio) e dois níveis de extrato de leveduras (com ou sem) e prebiótico (com ou sem). O desempenho das aves foi avaliado considerando o ganho de peso, o consumo de ração, a conversão alimentar e a viabilidade aos 42 dias de idade. Também foram avaliados o rendimento de carcaça e a morfometria intestinal. O calor ambiente prejudicou o desempenho e o rendimento de carcaça. A inclusão de prebiótico na ração pré-inicial aumentou o ganho de peso e melhorou a conversão alimentar das aves criadas no calor. A inclusão dos produtos na ração de frangos de corte criados em ambiente de calor e no frio tem efeito benéfico sobre as vilosidades das aves.