The infection density of symbionts is among the major parameters to understand their biological effects in host-endosymbionts interactions. Diaphorina citri harbors two bacteriome-associated bacterial endosymbionts (Candidatus Carsonella ruddii and Candidatus Profftella armatura), besides the intracellular reproductive parasite Wolbachia. In this study, the density dynamics of the three endosymbionts associated with the psyllid D. citri was investigated by real-time quantitative PCR (qPCR) at different developmental stages. Bacterial density was estimated by assessing the copy number of the 16S rRNA gene for Carsonella and Profftella, and of the ftsZ gene for Wolbachia. Analysis revealed a continuous growth of the symbionts during host development. Symbiont growth and rate curves were estimated by the Gompertz equation, which indicated a negative correlation between the degree of symbiont-host specialization and the time to achieve the maximum growth rate (t*). Carsonella densities were significantly lower than those of Profftella at all host developmental stages analyzed, even though they both displayed a similar trend. The growth rates of Wolbachia were similar to those of Carsonella, but Wolbachia was not as abundant. Adult males displayed higher symbiont densities than females. However, females showed a much more pronounced increase in symbiont density as they aged if compared to males, regardless of the incorporation of symbionts into female oocytes and egg laying. The increased density of endosymbionts in aged adults differs from the usual decrease observed during host aging in other insect-symbiont systems.

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The objective of this study was to evaluate the effect of betaine in methionine-and choline-reduced diets fed to broilers submitted to heat stress. In total, 1,408 male broilers were randomly distributed into eight treatments, according to 2 x 4 (environment x diet) factorial arrangement, with eight replicates of 2 birds each. Birds were reared environmental chambers under controlled temperature (25-26 °C) or cyclic heat-stressing temperature (25-31 °C). The following diets were tested: positive control (PC), formulated to meet broiler nutritional requirements; negative control (NC), with reduced DL-methionine and choline chloride levels; and with two supplementation levels of natural betaine to the negative control diet (NC+NB1 and NC+NB2). Live performance, carcass traits, and intestinal morphometrics were evaluated when broilers were 45 days of age. The results showed that all evaluated parameters were influenced by the interaction between environment and diet, except for breast meat drip loss. The breakdown of the interactions showed that birds fed the PC diet and reared in the controlled environment had greater breast drip loss than those submitted to the cyclic heat-stress environment. Birds submitted to cyclic heat stress and fed the PC diet presented the lowest feed intake. Feed conversion ratio was influenced only by diet. The FCR of broilers fed the NC+NB2 diet was intermediate relative to those fed the PC and NC diets. The addition of betaine in the diet, with 11.18% digestible methionine and 24.73% total choline reductions, did not affect broiler live performance, carcass yield, or intestinal morphometrics.

The intensification of livestock have increased the emission of pollutants to the environment, leading to a growing interest in seeking strategies that minimise these emissions. Studies have shown that it is possible to manipulate diets by reducing CP levels and thus reducing nitrogen (N) excretion, without compromising performance. However, there is no knowledge of any study that has focused on reducing N excretion and relating this reduction to individual amino acids. This study investigated the effect of dietary methionine + cysteine (MC) and threonine (THR), the two most limiting amino acids for broiler production, on nitrogen excretion (NE) and nitrogen deposition (ND) and determined the efficiency of utilisation of both amino acids for protein deposition. Six trials were conducted to measure the NE and ND in broiler chickens during three rearing phases in response to dietary amino acid. The efficiency of utilisation of the amino acids was calculated by linear regression of body protein deposition and the amino acid intake. Despite the differences between sexes and phases, the efficiency of utilisation was the same, being 0.60 and 0.59 for MC and THR, respectively. The rate of NE behaved exponentially, increasing with amino acid intake, and can exceed 50% of N intake, being higher than ND. On average, for a reduction in intake of each unit of MC or THR (mg) there is a reduction of 0.5% of NE. Although this reduction seems low, considering that it corresponds to changes in one amino acid only, the impact on a large scale would be significant. Knowledge of how animals respond to NE and ND/protein deposition according to amino acid dietary content may represent new efforts towards reducing the impact on environment.Keywords: amino acids, efficiency of utilisation, environmental pollution, nutrition, poultry ImplicationsThis study shows the effect of amino acids on nitrogen excretion and deposition and on their efficiency of utilisation for protein deposition by broilers. The nitrogen originating from the poultry is an environmental pollutant. Provision of higher amounts of amino acids, besides not increasing protein deposition, also causes increased nitrogen excretion. Meeting animal's amino acids requirements, provides greater efficiency of utilisation of these amino acids, without affecting protein deposition in the animals, and thus reduces nitrogen excretion. In this way, the management of amino acids in broilers diets may allow new efforts to reduce the impact of intensification of livestock. IntroductionThe intensification of livestock have significantly increased the emission of pollutants to the environment, leading to a growing interest in seeking alternatives that minimise these emissions. The European Union has already implemented laws regulating environmental pollution, especially in regard to the emission of nitrogen (N) compounds, considered to be a critical pollutants affecting life on earth (European Commission, 2007). N compounds are responsible for pollution of groundwater due to nitrate lea...

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ABSTRACT. The objective of this research study was to evaluate the effect of age on the apparent ileal digestibility coefficient of nutrients, gross energy and digestible energy of corn germ meal for broilers. Four digestibility trials were conducted using 280 broilers (Cobb 500) distributed in a completely randomized design with two treatments and five replications, repeated at four ages (10, 20, 30 and 40 days). The number of birds used in the tests was 10, 8, 6 and 4 birds per experimental unit at the different ages. The results were analyzed considering as dependent variable the apparent ileal digestibility of dry matter, crude protein, ether extract and gross energy, digestible dry matter, digestible crude protein, lipid and digestible energy; and ages (10, 20, 30 and 40 days) as the independent variable. The results for the variables showed that bird age exerted influence only in the ileal digestibility of dry matter and gross energy. The digestible energy of corn germ meal increased by about 13 kcal kg -1 day -1 up to the evaluated age (40 days).Keywords: corn coproducts, digestible energy, fat, ileum, partial collection.Efeito da idade de frangos de corte sobre a digestibilidade ileal do gérmen integral de milho RESUMO. Objetivou-se com esta pesquisa avaliar o efeito da idade sobre os coeficientes de digestibilidade ileal aparente dos nutrientes, da energia bruta e os valores de energia digestível do gérmen integral de milho para frangos de corte. Quatro ensaios de digestibilidade foram realizados com 280 aves de corte (Cobb 500) distribuídas em um delineamento experimental inteiramente casualizado, com quatro tratamentos e cinco repetições. Os tratamentos avaliados consistiram das diferentes idades das aves: 10, 20, 30 e 40 dias. A quantidade de aves utilizadas nos ensaios foram: dez, oito, seis e quatro em cada unidade experimental, nas diferentes idades avaliadas, respectivamente. Os resultados foram analisados considerando-se como variável dependente a digestibilidade ileal aparente da matéria seca, da proteína bruta, do extrato etéreo e da energia bruta, matéria seca digestível, proteína bruta digestível, extrato etéreo digestível e energia digestível e como variável independente as idades (10, 20, 30 e 40 dias). Os resultados obtidos para as variáveis analisadas revelaram que a idade da ave exerceu influência apenas nos coeficientes de digestibilidade ileal da matéria seca e da energia bruta. A energia digestível do gérmen integral de milho aumentou cerca de 13 kcal kg -1 dia -1 até a idade avaliada (40 dias).

Níveis de óleo de soja na dieta de poedeiras comerciais criadas em região de alta temperatura RESUMO Com o objetivo de avaliar o efeito da inclusão do óleo de soja em rações sobre o desempenho produtivo, qualidade da casca e parâmetros econômicos de poedeiras comerciais, realizou-se um experimento utilizando-se 160 aves da linhagem Hisex brown, com 40 semanas de idade. As aves foram distribuídas em delineamento inteiramente casualizado com cinco tratamentos e quatro repetições de oito aves por unidade experimental. Os tratamentos consistiram de dietas formuladas com 0,0; 1,0; 2,0; 3,0 e 4,0% de inclusão de óleo de soja e com o mesmo nível energético e nutricional. Os tratamentos não afetaram o peso das aves, a produção de ovos, consumo de ração, energia e proteína, conversão por dúzia de ovos e espessura de casca; entretanto, a inclusão do óleo de soja aumentou linearmente o peso dos ovos e, quadraticamente, às conversões por massa, energética e protéica de ovos, além do que a inclusão do óleo aumentou o custo da ração; conclui-se, então, que o óleo de soja aumenta o peso dos ovos, apresentando efeito a partir de 2% em rações à base de milho e farelo de soja, e que a sua utilização em níveis crescentes pode aumentar o custo da ração e diminuir a renda liquida, razão por que deve ser utilizado após uma análise econômica.Palavras-chave: poedeiras, produção de ovos, suplementação de gordura, óleo de soja Oil levels in the diet of laying hens maids in area of high temperature ABSTRACTThis objective was to evaluate the performance, quality of egg and economics parameters of laying hens feed with different levels of soybean oil in the diets. 166 laying hens, Hisex brown, 40 weekold were used and distributed in a completely randomized design in five treatments and four replications of 8 laying hens. The levels of the soybean oil were: 0, 1, 2, 3 e 4% in the diets with same energetic and nutritional levels. The treatments did not affect the live weight, eggs production, feed intake, energy and protein intake, conversion for dozen egg and shell thickness. However, the inclusion of the soybean oil showed linear effect in the egg weight and quadratic effect for mass, energetic, and protein conversion, besides the inclusion of this oil increased the cost of the ration. It is concluded that the soybean oil increase the egg weight, showing effect with 2% inclusion in the diet based on corn and soybean, and the utilization in increasing levels may increased the costs and decreased the net income, for that reason should be used only after economic analysis.

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