Description of a model to optimise the feeding of amino acids to growing pullets.

1. A nutrition model is described that may be used to optimise the amino acid nutrition of laying-type pullets prior to the onset of lay. It is not a method of optimising lifetime laying performance. 2. The potential growth and composition of the body, feathers, ovary and oviduct are described from hatching to the age at which sexual maturity is attained, from which the daily amino acid and energy requirements for the average individual in the population can be calculated. 3. There are two parts to the approach used, the first being a description of the model itself and the second being a description of how the required information was gathered. A number of assumptions made in developing the model are discussed. 4. The rates of maturing of the body, feather-free body and body protein of the DeKalb pullets used were shown to be constant at 0.017/d and those of feathers at 0.02/d. These are considerably slower than those of the oviduct and ovary (0.139 and 0.084/d respectively). The ovary attained a higher mature weight (78.4 vs. 58.7 g) than the oviduct. 5. The age at which the growth of the reproductive organs is initiated in the model is defined by the user. The daily amount of threonine required to meet the requirements for maintenance and potential growth of the developing tissues and organs is calculated for each day of the growing period from hatching to the age at which the first egg is laid. A method of calculating the required daily concentration of threonine in the feed is described, from which a feeding programme may be derived. 6. For the model to produce an optimum economic feeding programme for a population of laying-type pullets, more information than is available from this study is required. These issues are discussed in the paper.

The response to dietary threonine in laying-type pullets during growth.

1. This study aimed to provide information on the response of laying-type pullets to dietary threonine (THR) during three periods of growth prior to the onset of lay. Different batches of Dekalb White pullets were used in three separate trial periods (from 4 to 6, 8 to 11 and 13 to 16 weeks of age) using 8 dietary THR concentrations in each period, using a completely randomised design, and with each treatment being replicated 6 times, using 15 birds per replication in period 1 and 8 birds in periods 2 and 3. In period 1 the THR content (THRc) ranged from 2.3 to 7.6 mg/g, in period 2 from 1.7 to 5.5 mg/g, and in period 3 from 1.4 to 4.7 mg THR/g feed. 2. Body weight gain, food intake and the deposition of protein and lipid in the feather-free body and in the feathers were measured in each period. Linear regressions were fitted to all data falling below the break point defined by the broken stick regression, to estimate the efficiency of utilisation of THR. The maximum protein growth rate was 4.0 ± 0.2, 5.3 ± 0.4 and 3.5 ± 0.5 g/d in periods 1, 2 and 3, respectively. 3. The efficiency of utilisation of dietary THR for THR deposition in each period was the same, at 0.85 ± 0.1 mg/mg. As dietary THRc decreased, the amount of body lipid deposition increased. 4. With this information, it is possible to determine the daily requirement for THR for the potential growth of body and feather protein in growing pullets.

Effect of dietary betaine supplementation on the performance, carcass yield, and intestinal morphometrics of broilers submitted to heat stress

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.(AU)

Effect of lighting programs on broiler chickens performance, carcass yield and parts yield / Efeito de programas de luz sobre o desempenho e rendimento de carcaça, cortes comerciais e vísceras comestíveis de frangos de corte

An experiment was conducted to determine the effects of two lighting programs on performance, carcass yield and parts yield of broiler chickens. Nine-hundred-sixty Cobb male and female broiler chicks were used and distributed in a completely randomized design with 2 x 2 factorial arrangement (two sexes and two lighting programs: - increasing light: 1 to 14 days, 24L:0D; 15 to 21 days, 16L:8D; 22 to 29 days, 18L:6D; 30 to 40 days, 20L:4D and 41 to 49 days, 23L:1D; - continuous light: 23L:1D to 1 to 49 days of age) with four treatments and six replicates of 40 birds. In the starter phase, birds raised on increasing light program showed lower body weight gain and feed intake as compared to those submitted to continuous light program. However, in the total period of rearing no significant differences between treatments were observed. Carcass yield and parts yield showed no standard profile. In conclusion, a compensatory gain in the broiler chickens reared on increasing light program was observed.     KEY-WORDS: Broiler chickens. Lighting programs. Performance. Sex. Yield.

Effect of organic acid and plant extract on performance and quality egg of laying hens / Efeito de acidificantes e extratos vegetais sobre o desempenho e qualidade de ovos de poedeiras comerciais

The trial was conducted to evaluate the best level of organic acid inclusion and effect of plant extracts on the performance parameters and quality of eggs of laying. Lohmann LSL laying hem strain (256) at 40 weeks of age were distributed in a blocks in factorial design 4 x 2 (four acid levels and two levels of plant extract) with two blocks, two replications for each treatment in the block with eight birds for experimental unit. The birds were distributed in the blocks based in their weight. The treatments were: control (without additive), 200g/t of acid, 400g/t acid, 600g/t acid, 150 g/t of plant extract, 200g/t of acid + 150g/t of plant extract, 400g/t of acid + 150g/t of plant extract and 600g/t acid + 150g/t of plant extract. The experimental period was 84 days divided in three cycles of 28 days each. The association of organic acids with vegetal extract promoted highest percentage of production and feed conversion/twelve eggs. However, these additives did not affect the feed intake, Haugh units and specific gravity of eggs of the commercial laying hens in the end of production cycle. The inclusion of 400 g/t of acids plus 150 g/t extract can improved egg production.           KEY - WORDS:

Essa pesquisa foi conduzida com o objetivo verificar o melhor nível de inclusão e o efeito de ácidos orgânicos e extratos vegetais sobre os parâmetros de desempenho e qualidade de ovos de poedeiras comerciais. Utilizou-se 256 poedeiras da linhagem Lohmann LSL com 40 semanas de idade, distribuídas em delineamento de blocos ao acaso no esquema fatorial 4 x 2 (quatro níveis de ácido e dois níveis de extrato vegetal) com dois blocos, duas repetições por tratamento em cada bloco e oito aves por unidade experimental. As aves foram distribuídas nos blocos em função do peso. Os tratamentos foram: controle (sem aditivo), 200g/t de ácido, 400g/t ácido, 600g/t ácido, 150g/t de extrato vegetal, 200g/t de ácido + 150g/t de extrato vegetal, 400g/t de ácido + 150g/t de extrato vegetal e 600g/t ácido + 150g/t de extrato vegetal. O período de avaliação foi de 84 dias divididos em três ciclos de 28 dias. A associação do acidificante com o extrato vegetal promoveu maior porcentagem de postura e conversão alimentar por dúzia de ovos. No entanto, a administração isolada ou asso

EFFECT OF LIGHTING PROGRAMS ON BROILER CHICKENS PERFORMANCE, CARCASS YIELD AND PARTS YIELD. / EFEITO DE PROGRAMAS DE LUZ SOBRE O DESEMPENHO E RENDIMENTO DE CARCAÇA, CORTES COMERCIAIS E VÍSCERAS COMESTÍVEIS DE FRANGOS DE CORTE.

  An experiment was conducted to determine the effects of two lighting programs on performance, carcass yield and parts yield of broiler chickens. Nine-hundred-sixty Cobb male and female broiler chicks were used and distributed in a completely randomized design with 2 x 2 factorial arrangement (two sexes and two lighting programs: - increasing light: 1 to 14 days, 24L:0D; 15 to 21 days, 16L:8D; 22 to 29 days, 18L:6D; 30 to 40 days, 20L:4D and 41 to 49 days, 23L:1D; - continuous light: 23L:1D to 1 to 49 days of age) with four treatments and six replicates of 40 birds. In the starter phase, birds raised on increasing light program showed lower body weight gain and feed intake as compared to those submitted to continuous light program. However, in the total period of rearing no significant differences between treatments were observed. Carcass yield and parts yield showed no standard profile. In conclusion, a compensatory gain in the broiler chickens reared on increasing light program was observed.     KEY-WORDS: Broiler chickens. Lighting programs. Performance. Sex. Yield.    

EFFECT OF ORGANIC ACID AND PLANT EXTRACT ON PERFORMANCE AND QUALITY EGG OF LAYING HENS / EFEITO DE ACIDIFICANTES E EXTRATOS VEGETAIS SOBRE O DESEMPENHO E QUALIDADE DE OVOS DE POEDEIRAS COMERCIAIS

                The trial was conducted to evaluate the best level of organic acid inclusion and effect of plant extracts on the performance parameters and quality of eggs of laying. Lohmann LSL laying hem strain (256) at 40 weeks of age were distributed in a blocks in factorial design 4 x 2 (four acid levels and two levels of plant extract) with two blocks, two replications for each treatment in the block with eight birds for experimental unit. The birds were distributed in the blocks based in their weight. The treatments were: control (without additive), 200g/t of acid, 400g/t acid, 600g/t acid, 150 g/t of plant extract, 200g/t of acid + 150g/t of plant extract, 400g/t of acid + 150g/t of plant extract and 600g/t acid + 150g/t of plant extract. The experimental period was 84 days divided in three cycles of 28 days each. The association of organic acids with vegetal extract promoted highest percentage of production and feed conversion/twelve eggs. However, these additives did not affect the feed intake, Haugh units and specific gravity of eggs of the commercial laying hens in the end of production cycle. The inclusion of 400 g/t of acids plus 150 g/t extract can improved egg production.           KEY - WORDS:      

Essa pesquisa foi conduzida com o objetivo verificar o melhor nível de inclusão e o efeito de ácidos orgânicos e extratos vegetais sobre os parâmetros de desempenho e qualidade de ovos de poedeiras comerciais. Utilizou-se 256 poedeiras da linhagem Lohmann LSL com 40 semanas de idade, distribuídas em delineamento de blocos ao acaso no esquema fatorial 4 x 2 (quatro níveis de ácido e dois níveis de extrato vegetal) com dois blocos, duas repetições por tratamento em cada bloco e oito aves por unidade experimental. As aves foram distribuídas nos blocos em função do peso. Os tratamentos foram: controle (sem aditivo), 200g/t de ácido, 400g/t ácido, 600g/t ácido, 150g/t de extrato vegetal, 200g/t de ácido + 150g/t de extrato vegetal, 400g/t de ácido + 150g/t de extrato vegetal e 600g/t ácido + 150g/t de extrato vegetal. O período de avaliação foi de 84 dias divididos em três ciclos de 28 dias. A associação do acidificante com o extrato vegetal promoveu maior porcentagem de postura e conversão alimentar por dúzia de ovos. No entanto, a administração isolada ou asso

EFFECT OF LIGHTING PROGRAMS ON BROILER CHICKENS PERFORMANCE, CARCASS YIELD AND PARTS YIELD. / EFEITO DE PROGRAMAS DE LUZ SOBRE O DESEMPENHO E RENDIMENTO DE CARCAÇA, CORTES COMERCIAIS E VÍSCERAS COMESTÍVEIS DE FRANGOS DE CORTE.

  An experiment was conducted to determine the effects of two lighting programs on performance, carcass yield and parts yield of broiler chickens. Nine-hundred-sixty Cobb male and female broiler chicks were used and distributed in a completely randomized design with 2 x 2 factorial arrangement (two sexes and two lighting programs: - increasing light: 1 to 14 days, 24L:0D; 15 to 21 days, 16L:8D; 22 to 29 days, 18L:6D; 30 to 40 days, 20L:4D and 41 to 49 days, 23L:1D; - continuous light: 23L:1D to 1 to 49 days of age) with four treatments and six replicates of 40 birds. In the starter phase, birds raised on increasing light program showed lower body weight gain and feed intake as compared to those submitted to continuous light program. However, in the total period of rearing no significant differences between treatments were observed. Carcass yield and parts yield showed no standard profile. In conclusion, a compensatory gain in the broiler chickens reared on increasing light program was observed.     KEY-WORDS: Broiler chickens. Lighting programs. Performance. Sex. Yield.    

EFFECT OF ORGANIC ACID AND PLANT EXTRACT ON PERFORMANCE AND QUALITY EGG OF LAYING HENS / EFEITO DE ACIDIFICANTES E EXTRATOS VEGETAIS SOBRE O DESEMPENHO E QUALIDADE DE OVOS DE POEDEIRAS COMERCIAIS

                The trial was conducted to evaluate the best level of organic acid inclusion and effect of plant extracts on the performance parameters and quality of eggs of laying. Lohmann LSL laying hem strain (256) at 40 weeks of age were distributed in a blocks in factorial design 4 x 2 (four acid levels and two levels of plant extract) with two blocks, two replications for each treatment in the block with eight birds for experimental unit. The birds were distributed in the blocks based in their weight. The treatments were: control (without additive), 200g/t of acid, 400g/t acid, 600g/t acid, 150 g/t of plant extract, 200g/t of acid + 150g/t of plant extract, 400g/t of acid + 150g/t of plant extract and 600g/t acid + 150g/t of plant extract. The experimental period was 84 days divided in three cycles of 28 days each. The association of organic acids with vegetal extract promoted highest percentage of production and feed conversion/twelve eggs. However, these additives did not affect the feed intake, Haugh units and specific gravity of eggs of the commercial laying hens in the end of production cycle. The inclusion of 400 g/t of acids plus 150 g/t extract can improved egg production.           KEY - WORDS:      

Essa pesquisa foi conduzida com o objetivo verificar o melhor nível de inclusão e o efeito de ácidos orgânicos e extratos vegetais sobre os parâmetros de desempenho e qualidade de ovos de poedeiras comerciais. Utilizou-se 256 poedeiras da linhagem Lohmann LSL com 40 semanas de idade, distribuídas em delineamento de blocos ao acaso no esquema fatorial 4 x 2 (quatro níveis de ácido e dois níveis de extrato vegetal) com dois blocos, duas repetições por tratamento em cada bloco e oito aves por unidade experimental. As aves foram distribuídas nos blocos em função do peso. Os tratamentos foram: controle (sem aditivo), 200g/t de ácido, 400g/t ácido, 600g/t ácido, 150g/t de extrato vegetal, 200g/t de ácido + 150g/t de extrato vegetal, 400g/t de ácido + 150g/t de extrato vegetal e 600g/t ácido + 150g/t de extrato vegetal. O período de avaliação foi de 84 dias divididos em três ciclos de 28 dias. A associação do acidificante com o extrato vegetal promoveu maior porcentagem de postura e conversão alimentar por dúzia de ovos. No entanto, a administração isolada ou asso

Preferred amino acids and thermostability

Most organisms grow at temperatures from 20 to 50 degrees C, but some prokaryotes, including Archaea and Bacteria, are capable of withstanding higher temperatures, from 60 to >100 degrees C. Their biomolecules, especially proteins, must be sufficiently stable to function under these extreme conditions; however, the basis for thermostability remains elusive. We investigated the preferential usage of certain groupings of amino acids and codons in thermally adapted organisms, by comparative proteome analysis, using 28 complete genomes from 18 mesophiles (M), 4 thermophiles (T), and 6 hyperthermophiles (HT). Whenever the percent of glutamate (E) and lysine (K) increased in the HT proteomes, the percent of glutamine (Q) and histidine (H) decreased, so that the E + K/Q + H ratio was >4.5; it was <2.5 in the M proteomes, and 3.2 to 4.6 in T. The E + K/Q + H ratios for chaperonins, potentially thermostable proteins, were higher than their proteome ratios, whereas for DNA ligases, which are not necessarily thermostable, they followed the proteome ratios. Analysis of codon usage revealed that HT had more AGR codons for Arg than they did CGN codons, which were more common in mesophiles. The E + K/Q + H ratio may provide a useful marker for distinguishing HT, T and M prokaryotes, and the high percentage of the amino acid couple E + K, consistently associated with a low percentage of the pair Q + H, could contribute to protein thermostability. The preponderance of AGR codons for Arg is a signature of all HT so far analyzed. The E + K/Q + H ratio and the codon bias for Arg are apparently not related to phylogeny. HT members of the Bacteria show the same values as the HT members of the Archaea; the values for T organisms are related to their lifestyle (intermediate temperature) and not to their domain (Archaea) and the values for M are similar in Eukarya, Bacteria and Archaea

Bacteria isolated from a sugarcane agroecosystem: their potential production of polyhydroxyalcanoates and resistance to antibiotics

In this investigation, a sugarcane agroecosystem at a coastal tableland, in the northeast of Brazil, was screened to obtain bacteria strains able to synthesize poly-ß-hydroxyalkanoates (PHA), using sucrose as the main carbon source. The potential to synthesize PHA was tested qualitatively by Sudan Black staining of colonies growing in different carbon sources: sucrose, glucose, fructose, propionate and cellulose. In a typical sugarcane crop management system, the plantation is burned before harvesting and vinasse, a by-product of alchohol production, is used in a fertirrigation system causing, probably, selective pressures on the microbiota of natural environments. Eighty-two bacteria strains, belonging to 16 different genera and 35 different species, were isolated. The data showed that 11 strains (ca 13 per cent), nine of which belonging to the genus Pseudomonas, presented a strong Sudan Black staining in several carbon sources tested and, simultaneously, showed multiple resistance to antibiotics. Resistance to antibiotics is an advantageous feature for the biotechnological production of PHAs. The total number of isolates with multiple resistance to antibotics was 73, and 38 (per cent) of them belong to the genus, Pseudomonas. Among the isolates ca, 86 (per cent) and 43 (per cent) grew in the presence of 10-100U/ml of penicillin and/or 100-300 mg/ml of virginiamycin, respectively. These antiotics are utilized in the alcohol distillery we investigated. The results suggest that some agroecosystem environments could be considered as habitats where bacteria are submitted to nutritional unbalanced conditions, resulting in strains with potential ability to produce PHAs, and also, to an increase in the microbial diversity.

Effect of heat shock on S6 phosphorylation during the development of Blastocladiella emersonii.

Changes in phosphorylation of ribosomal protein S6 during heat shock, induction of thermotolerance and recovery from heat shock at different stages of Blastocladiella emersonii development were investigated. Independently of the initial state of S6 phosphorylation (maximal or intermediate), a rapid and complete dephosphorylation of S6 is induced by heat shock and S6 remains unphosphorylated during the acquired thermotolerance. During recovery from heat shock rephosphorylation of S6 occurs always to the levels characteristic of that particular stage, coincidently with the turn off of heat shock protein synthesis.

Influence of RP4 plasmid on extracellular protease secretion by Proteus mirabilis.

The transference by conjugation of protease genetic information between Proteus mirabilis strains only occurs upon mobilization by a conjugative plasmid such as RP4 (Inc P group). Upon receiving the RP4 plasmid, the level of proteolytic activity of the protease-excreting P. mirabilis is reduced to about 50%. A similar phenomenon occurs when the protease character is mobilized by the RP4 plasmid from the above transconjugant to a non-protease-excreting recipient strain. The molecular mechanism underlying the interference of R plasmids with proteolytic activity remains to be elucidated but there is evidence suggesting that some alteration in the bacterial envelope might be involved.

Analysis of Blastocladiella emersonii ribosomal proteins in four two-dimensional gel electrophoresis systems.

Ribosomal proteins of the aquatic fungus Blastocladiella emersonii were isolated and characterized on four different two-dimensional polyacrylamide gel electrophoresis systems. 40S and 60S ribosomal subunit proteins from zoospores were identified. The position of every protein was determined in each electrophoretic system using the "four-corners" method (Madjar et al., Molecular and General Genetics, 171: 121-134, 1979). Thirty-two and 39 proteins were identified in the 40S and 60S ribosomal subunits, respectively. The molecular weights of individual proteins in the 40S subunit ranged from 10 000 to 37 000, with a number-average molecular weight of 20 000. The molecular weight range for the 60S subunit was 13 000-51 000 with a number-average molecular weight of 21 000. Proteins from ribosomes of different cell types were compared and found to be qualitatively indistinguishable. The only consistent difference in the patterns of proteins was in the S6 protein of the 40S subunit, which is the major phosphoprotein of Blastocladiella ribosomes.

Sensibilidade de linhagens de Proteus mirabilis portadores do plasmidio R ao desoxicolato de sodio. / Sensitivity of Proteus mirabilis strains carrying plasmid R to sodium deoxycholate

A presenca de plasmidio R, em clones excretores e nao excretores da protease, de uma linhagem de Proteus mirabilis, confere maior sensibilidade ao desoxicolato de sodio

Acao de alguns agentes curagenicos na perda da excrecao de protase em Proteus mirabilis. / Effects of some cu excretion of Proteus mirabilis

Drogas curagenicas, como brometo de etidio acriflavina e mitomicina C, aumentam grandemente, a conversao de celulas excretoras de protease instaveis de Proteus mirabilis em celulas nao excretoras. Esse efeito nao ocorre sobre celulas excretoras estaveis de protease. A rifampicina apenas seleciona celulas protease-negativas, por eliminacao preferencial de celulas excretoras.Temperaturas superiores a fisiologica nao sao efetivas na perda de excrecao de protease em linhagens de P. mirabilis que excretam protease de maneira instavel