L.J.C. Lara

Qualidade de ovos de consumo submetidos a diferentes condições de armazenamento

The internal quality of 768 commercial white eggs from 40-week-old Hy-Line laying hens was evaluated after storage under different conditions. The eggs were submitted to treatments in a factorial scheme of 2x4x8, being two types of package (using plastic film or not), four periods of storage (zero, five, 10, and 15 days), and eight refrigerated storage times (zero, five, 10, 15, 20, 25, 30 and 35 days). The values of Haugh Unities (HU) and albumen pH were measured. The HU values significantly decreased (P<0.05) during storage mainly at room temperature. Wrapping the eggs packages with plastic film showed efficient in preserving their internal quality since it kept HU higher for a longer storage time. The pH values of the eggs increased during the storage time (P<0.05), independently of both storage temperature and packaging. It was concluded that temperature and time of storage of eggs influenced on the values of HU and wrapping the eggs packages with plastic film improved their internal quality.

Efeito da classificação dos ovos sobre o rendimento de incubação e os pesos do pinto e do saco vitelino

Two experiments were carried out to study the effects of broiler breeder age on weight uniformity of 1,080 eggs and yolks, and the effects of 9,216 eggs classified prior to setting on hatchability, embryonic mortality, and the relationship between chick and yolk sac weights. In the first study, the three treatments were eggs from broiler breeders on 31st (M31), 38th (M38), and 43th (M43)-week of age. In the second study, eggs produced by three broiler breeders flocks (31st, 38th, and 43th wk of age) were divided in six treatments; A: eggs weighting from 66 to 72g, 33,3% of them produced by broiler breeders of different ages; B: eggs weighting from 58 to 65g, 33,3% of them produced by broiler breeders of different ages; C: eggs weighting from 52 to 57g, 33,3% of them produced by broiler breeders of different ages; D: eggs from 31-wk-old broiler breeders, weighting from 52 to 72g; E: eggs from 38-wk-old broiler breeders, weighting from 52 to 72g; F: eggs from 43-wk- old broiler breeders weighting from 52 to 72g. Eggs produced by M31 had egg and yolk weights more uniform than the eggs collected from M43. Treatment A had the worst hatchability, higher embryonic mortality after 15 days of incubation, and produced heavier hatched chicks with superior absolute and relative weights of yolk sac.

Efeito de fontes lipídicas sobre o desempenho de frangos de corte

A completely randomized design with six replicates of 30 birds per experimental unit was used to evaluate the effect of five fat sources of diets (soybean oil, poultry fat, acidulated soybean oil soapstock and a mix of soybean oil plus poultry fat and soybean oil plus acidulated soybean oil soapstock) on the performance of male Ross broilers, during the growing period (1-45 days of age). The diets for each phase were isonutritional. Broilers fed on soybean oil showed higher weight gain in comparison to the birds fed on diets containing acidulated soybean oil soapstock (P<0.05), but no differences were observed among the other treatments. The feed intake of birds fed on soybean oil was higher compared to the birds fed on acidulated soybean soapstock diet and mix of soybean oil plus acidulated soybean oil soapstock diet. No treatment effect was observed for feed:weight gain ratio and viability. Soybean oil diet resulted in better broiler performance in comparison to acidulated soybean oil soapstock diet.

Efeito do período de jejum pré-abate sobre o rendimento de carcaça de frango de corte

Avaliaram-se os efeitos de cinco periodos (quatro, oito, 12, 14 e 16 horas) de jejum pre-abate sobre a perda de peso e rendimento de carcaca e cortes de frangos de corte. Foram utilizados 240 frangos (120 machos e 120 femeas), linhagem Cobb, criados ate 44 dias de idade. No 44o dia, as aves foram separadas de acordo com o periodo de jejum (tratamentos) e o sexo, cada tratamento com 24 repeticoes. Nos tratamentos de quatro, oito, 12 e 16 horas, o jejum foi alimentar e no tratamento de 14 horas, o jejum foi alimentar e hidrico. O teste utilizado para as analises das medias foi o SNK (Student-Newman-Keuls). Foram analisadas as seguintes variaveis: perda de peso vivo apos o jejum, taxa de absorcao de agua pela carcaca, rendimentos da carcaca inteira e dos cortes comerciais coxa e sobrecoxa, peito, dorso, asa, pes e cabeca e pescoco, rendimentos da moela e figado e peso dos intestinos. Os periodos de jejum de oito, 12, 14, e 16 horas apresentaram maior rendimento de carcaca, sendo superiores ao periodo de quatro horas de jejum (P 0,05). As femeas absorveram mais agua do que os machos, e apresentaram rendimentos de carcaca e cortes comerciais superiores aos dos machos (P<0,05).

Efeitos da forma física da ração sobre a digestibilidade dos nutrientes e desempenho de frangos de corte

Two experiments were carried out in order to compare the effects of physical form of ration on feed digestibility and performance of broiler chickens. In the first experiment 480 day-old male Ross broiler chicks were used during the 42 days of trial, following a completely randomized design of three treatments: three physical forms of ration (mash, pellet and expanded-pellet) with eight replicates of twenty birds each. In the second experiment 900 day-old male Ross broiler chicks were used during the 42 day of trial, following the same design, but with 10 replications of 30 birds each. No significant difference in the coefficient of dry matter metabolization was observed. The metabolizable protein was higher in pellet-expanded ration and lower in mash ration (P<0.05). The processing of diet significantly increased the metabolizable ether extract (P<0.05) and values of 68.87, 74.64 and 74.44% were observed for mash, pellet and expanded-pellet rations, respectively. Body weight of broilers increased as the intensity of processing of ration reaching 2.597, 2.828 and 2.874kg for mash, pellet and expanded-pellet rations, respectively (P<0.05). Birds fed processed rations showed higher feed consumption and lower feed conversion (P<0.05). The physical form of ration did not affect viability of birds.

HPLC-MS/MS method validation for the detection of carbadox and olaquindox in poultry and swine feedingstuffs

Carbadox (CBX) and olaquindox (OLA) were used in poultry and swine feed for growth promotion, to improve feed efficiency and increase the rate of weight gain. However, the use of these agents in feedingstuffs was prohibited because of concerns about their toxicity. Regulatory laboratories are required to have suitably validated analytical methods to ensure compliance with the ban. A quantitative and confirmatory method for determining the presence of CBX and OLA in poultry and swine feed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed, optimized, and validated. The analytes extraction was performed with a mixture of water and acetonitrile (1:1v/v) and cleanup with hexane and C18 (dispersive phase). The method was evaluated by the following parameters: specificity, linearity, matrix effect, decision limits (CCα), detection capability (CCβ), accuracy, precision, limits of detection (LoD), limits of quantification (LoQ) and measurement uncertainty. The validated method presented a broad linear study range and no significant matrix effect. The limit of detection (LoD) was defined at 9 μg kg(-1) for CBX and 80 μg kg(-1) for OLA, and the limit of quantification (LoQ) was defined at 12 μg kg(-1) and 110 μg kg(-1) for CBX and OLA, respectively. The accuracy of the method was adequate for CBX and OLA. The recovery values found in the repeatability conditions were 99.41% for CBX and 104.62% for OLA. Under intralaboratory reproducibility conditions, the values were 98.63% for CBX and 95.07% for OLA. It was concluded that the performance parameters demonstrated total method adequacy for the detection and quantification of CBX and OLA in poultry and swine feedingstuffs.

Efeito do nível de ácido linoléico na ração de matrizes pesadas sobre o peso, composição e eclosão dos ovos

The effect of diet linoleic acid level on egg weight, egg composition, hatchability, chick weight, yolk sac percentage relative to chick weight and yolk fatty acid composition of broiler breeders Ross 305, from 27 to 40 weeks of age, were evaluated using two diets with two levels of linoleic acid. Egg weight and linoleic acid yolk composition were higher for diet with 1.93% of linoleic acid than for diet with 1.48% (59.5g vs 59.0g and 19.5% vs 15.5%, respectively). No linoleic acid effects on yolk, albumen, egg shell, yolk sac percentage and hatchability and chick weight were observed.

Influência da forma física da ração e da linhagem sobre o desempenho e rendimento de cortes de frangos de corte

Avaliou-se o efeito da forma fisica da racao sobre o desempenho e o rendimento de cortes de duas linhagens de frangos de corte, Cobb e Ross. Foram utilizados 900 frangos machos, criados em galpao experimental, com idades entre um a 45 dias. Os tratamentos foram definidos pela linhagem e forma fisica da racao da seguinte forma: (T1) racao farelada a vontade, (T2) racao peletizada a vontade e (T3) racao peletizada controlada. Para avaliacao do desempenho, o delineamento experimental foi o inteiramente ao acaso, em arranjo fatorial 3 x 2 (tres dietas e duas linhagens) e cinco repeticoes, sendo cada repeticao composta de 30 aves. Para a avaliacao do rendimento de cortes da carcaca, o delineamento foi o mesmo, com excecao do numero de repeticoes, que foi de 30, sendo cada ave considerada como uma repeticao. A racao peletizada controlada reduziu o ganho de peso em relacao a peletizada a vontade em 4,7% e melhorou a viabilidade da linhagem Cobb em 10%. Independentemente da linhagem, maiores ganhos de peso foram obtidos quando as aves foram alimentadas com racao peletizada a vontade. A restricao alimentar favoreceu a conversao alimentar das aves em 2%. A linhagem nao influenciou os parâmetros de rendimento de cortes e porcentagens de orgaos digestivos avaliados. A peletizacao favorece o desempenho de frangos de corte.

Efeitos das condições ambientais no período entre a postura e o armazenamento de ovos de matrizes pesadas sobre o rendimento de incubação

Avaliou-se o efeito das condicoes ambientais no periodo entre a postura e o armazenamento de ovos sobre o rendimento de incubacao de 2.742 ovos de matrizes pesadas da linhagem Ross com 31 semanas de idade. Os tratamentos foram definidos pelo periodo de permanencia dos ovos sob temperatura ambiente do galpao antes do armazenamento. Para cada tratamento foram utilizados 860 ovos, distribuidos em 10 repeticoes de 86 ovos cada. No tratamento A, os ovos foram enviados para a sala fria imediatamente apos a coleta; no B, foram enviados para a sala fria apos cinco horas de permanencia no galpao; e, no C, permaneceram no galpao por 10 horas, antes de serem enviados para a sala fria. As condicoes ambientais da sala fria foram: temperatura 18,2 a 21,0 oC e umidade relativa do ar de 72,8 a 76,8%. O periodo de armazenamento dos ovos foi de quatro dias. A mortalidade embrionaria no tratamento A foi maior que no tratamento B (P<0,05). A eclosao dos ovos do tratamento B foi maior que aquela do tratamento A (P<0,05). O peso dos pintos do tratamento A foi maior que aqueles do tratamento C (P<0,05). O melhor rendimento de incubacao foi obtido quando os ovos foram resfriados cinco horas apos a postura.The effect on hatchability of time post-oviposition until initiation of cool storage was examined using 2,742 eggs from 31-week-old Ross hens. Treatments were defined by the length of time that eggs remained at breeder house temperature, prior to cool storage. In treatments A, B and C, respectively, eggs were taken to the cooling room immediately after collection, after 5 hours in the aviary or after 10 hours in the aviary. From each treatment, 860 eggs were distributed into 10 replicates of 86 eggs each and stored for 4 days at 18.2 - 21.0oC and 75% humidity. After cool storage, they were incubated. Embryo mortality in treatment A was higher than in B (P<0.05). The hatchability of eggs of treatment B was higher (P<0.05) than that of treatment A. Average chick weight at hatching was higher for treatment A than for treatment C (P<0.05). Eggs that were cooled beginning five hours after oviposition produced the highest incubation yield.

Effect of energy, lysine and methionine and cystine levels on performance and carcass yield of broiler chickens

The effects of dietary energy, lysine and methionine + cystine levels on performance, carcass and cuts yields of male and female broiler chickens were evaluated. The experiment was analyzed as a completely randomized experimental design in a 3 × 2 factorial arrangement composed by six diets and eight replications (four males and four females). The diets consisted of energy (low, middle and high) and lysine and methionine + cystine (standard and + 10%) levels and of raising period (1 to 45 days old). Male broilers fed diets with 3,000, 3,100 and 3,200 kcal/kg, respectively, in the initial, growing and standard levels of amino acids showed better weight gain at 45 days old, however, for the best breast yield, the highest amino acid level was the most indicated. Middle energy and high amino acids levels are indicated for greater weight up to 40 days old, in females.The effects of dietary energy, lysine and methionine + cystine levels on performance, carcass and cuts yields of male and female broiler chickens were evaluated. The experiment was analyzed as a completely randomized experimental design in a 3 × 2 factorial arrangement composed by six diets and eight replications (four males and four females). The diets consisted of energy (low, middle and high) and lysine and methionine + cystine (standard and + 10%) levels and of raising period (1 to 45 days old). Male broilers fed diets with 3,000, 3,100 and 3,200 kcal/kg, respectively, in the initial, growing and standard levels of amino acids showed better weight gain at 45 days old, however, for the best breast yield, the highest amino acid level was the most indicated. Middle energy and high amino acids levels are indicated for greater weight up to 40 days old, in females.