Effects of egg storage time on spread of hatch, chick quality, and chick juvenile growth

A total of 1,800 incubating eggs produced by a commercial flock of Cobb broiler breeders was used to determine the effects of storage duration (3 or 18 d) on spread of hatch and chick quality. Chick relative growth (RG) at the end of 7 d of rearing was also determined as a measure of the chick performance. Chick quality was defined to encompass several qualitative characteristics and scored according to their importance. Eggs stored for 3 d hatched earlier than those stored for 18 d (P < 0.05). Hatching was normally distributed in both categories of eggs, and the spread of hatch was not affected by storage time (P = 0.69). Storage duration of 18 d reduced the percentage of day-old chick with high quality as well as average chick quality score (P < 0.05). RG varied with length of egg storage, quality of day-old chick, and the incubation duration (P < 0.05). Eighteen-day storage of eggs not only resulted in longer incubation duration and lower quality score but also depressed RG. Chick quality as defined in this study was correlated to RG and storage time. It was concluded that day-old chick quality may be a relatively good indicator of broiler performance. The results suggest however that in order to improve performance prediction power of chick quality, it would be better to define it as a combination of several qualitative aspects of the day-old chick and the juvenile growth to 7 d.

EFFECTS OF CAFFEINE ON FECUNDITY, EGG-LAYING CAPACITY, DEVELOPMENT TIME AND LONGEVITY IN DROSOPHILA-PROSALTANS

In Drosophila prosaltans reared on culture medium with caffeine (50-mu-g/ml, 100-mu-g/ml, 1000-mu-g/ml and 1500-mu-g/ml), fecundity decreased with increasing dosage. Other effects were (a) an approximately one day increase in development time of flies at 1000 and 1500-mu-g/ml, (b) a decrease of egg laying capacity, with increasing dosage and (c) a decrease of longevity when virgin males and females or mated males were analyzed. Mated treated females, however showed, in most experiments, greater longevity than the controls, thus suggesting a benefit of the partial blockage of reproduction caused by caffeine.

Rheological properties and fluid dynamics of egg yolk

The rheological behavior of egg yolk was studied at a range of temperatures (277-333 K) using a concentric cylinder viscometer. Rheological behavior was pseudoplastic and flow curves fitted by the power law model. The consistency and behavior indexes, dependent on temperature, were expressed by an Arrhenius-type equation. The rheological parameters, together with experimental values of pressure loss in tube flow were used to calculate friction factors. The good agreement between predicted and observed values confirmed the reliability of the equations proposed for describing the flow behavior of the egg yolk. (c) 2005 Published by Elsevier Ltd.

Density, heat capacity and thermal conductivity of liquid egg products

Density, heat capacity and thermal conductivity of liquid egg products, such as egg white, egg yolk, whole egg and various white and yolk blends, were determined as affected by temperature and water content ranging from 273 to 311 K and 51.8 to 88.2% (mass), respectively. Polynomial models fitted the experimental data very well, showing a linear relationship both for temperature and water content. (c) 2005 Published by Elsevier Ltd.

Viscoelasticity of frozen/thawed egg yolk as affected by salts, sucrose and glycerol

Based on dynamic rheological measurements, sucrose, glycerol and magnesium chloride (MgCl2) prevented egg yolk gelation at concentrations of 2% and higher, These additives showed improved cryoprotectant effects as their concentrations were increased, Sodium chloride (NaCl) at higher than 2% also prevented gelation but at 10%, it caused a considerable increase in viscosity of unfrozen yolk, Calcium chloride (CaCl2) showed an opposite effect, promoting protein coagulation before freezing, Samples with 2% CaCl2 gelled completely after 36h at -24 degrees C, Before freezing, potassium chloride (KCl) in the range 2-10% had an effect similar to that of NaCl, However, after freezing its effect changed, Yolk with 2% KCl, frozen 36h at -24 degrees C, showed very elastic behavior.

Estimates of genetic parameters, and cluster and principal components analyses of breeding values related to egg production traits in a White Leghorn population

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

Effects of storage time on incubating egg gas pressure, thyroid hormones, and corticosterone levels in embryos and on their hatching parameters

Incubating eggs (1,800 total) produced by a commercial flock of Cobb broiler breeders were used to determine the effects of storage duration (3 and 18 d) on gas partial pressure, thyroid hormones, and hatching parameters. Partial pressure of oxygen (pO2) and carbon dioxide (pCO2) were measured on d 18 and at internal pipping (IP) during incubation. Blood samples were collected for determination of triiodothyronine (T3), thyroxine (T4), and corticosterone concentrations in the embryos at IP and in newly hatched chicks. From 464 to 510 h of incubation, eggs were checked individually every 2 h to determine the timing and duration of IP, external pipping (EP), and total hatching time. At 18 d of incubation and at IP, pCO2 was greater in air cell of eggs stored for 3 d compared to those stored for 18 d (P < 0.05), but pO2 was greater in eggs stored for 18 d. At IP, T3 and corticosterone levels were higher in plasma of the embryos of eggs stored for 3 d compared to those stored for 18 d, but it was the reverse in newly hatched chicks (P < 0.05). Embryos from eggs stored for 18 d required more time to complete IP compared to embryos of eggs stored for only 3 d (P < 0.05), whereas the duration of EP was not affected by storage. The overall longer incubation was, however, not only due to prolonged IP but also to later occurrence of IP. It was concluded that prolonged IP as a result of long storage may be related to the late increase in corticosterone level, which may be a necessary stimulus for higher T 3/T4 ratio, late increase in pCO2 level, and decrease in pO2. The effect of long storage was a delay in hatching and a continuous increase in T3 due to higher corticosterone levels between IP and hatching, which may be an indication of the more stressful event of hatching of embryos from eggs stored longer. Differences in pCO2, pO2, T3, T4, and corticosterone levels in the incubating eggs may be manifestations of these changes culminating in altered hatching parameters and consequently differences in chick quality and growth potentials.

Gonad development in females of fiddler crab Uca rapax (Crustacea, Brachyura, Ocypodidae) using macro and microscopic techniques

The morphology of the ovaries in Uca rapax (Smith, 1870) was described based on macroscopic and microscopic analysis. Females were collected in Itamambuca mangrove, Ubatuba, state of São Paulo, Brazil. In the laboratory, 18 females had their ovaries removed and prepared for histology. Each gonad developmental stage was previously determined based on external and macroscopic morphology and afterwards each stage was microscopically described. The ovaries of U. rapax showed a pronounced macroscopic differentiation in size and coloration with the maturation of the gonad, with six ovarian developmental stages: immature, rudimentary, developing, developed, advanced and spent. During the vitellogenesis, the amount of oocytes in secondary stage increases in the ovary, resulting in a change in coloration of the gonad. Oogonias, primary oocytes, secondary oocytes and follicular cells were histologically described and measured. In female's ovaries of U. rapax the modifications observed in the oocytes during the process of gonad maturation are similar to descriptions of gonads of other females of brachyuran crustaceans. The similarities are specially found in the morphological changes in the reproductive cells, and also in the presence and arrange of follicle cells during the process of ovary maturation. When external morphological characteristics of the gonads were compared to histological descriptions, it was possible to observe modifications that characterize the process in different developmental stages throughout the ovarian cycle and, consequently, the macroscopic classification of gonad stages agree with the modifications of the reproductive cells.

The reproductive biology and cycle of Rioraja agassizi (Müller and Henle, 1841) (Chondrichthyes: Rajidae) in southeastern Brazil, SW Atlantic Ocean

Specimens of Rioraja agassizi were collected at Guarujá pier, São Paulo State, Brazil, from March 2005 to March 2006. A total of 275 males were captured. Based on the analysis of the clasper length, gonad weight, clasper gland length, alar thorns and lobule diameter, the size-at-maturity was estimated to be 32 cm. There were 1049 females in the record. Size-at-maturity was calculated in 40 cm. Sexual resting females were observed. Gonadosomatic and hepatosomatic indexes varied significantly in both sexes throughout the year. However, ovulation, egg-laying and presence of sperm in the seminal vesicle were observed all year round. For this reason, an annual cycle with at least one peak in the sexual activity is proposed for this species.

Genetic parameters and principal component analysis for egg production from White Leghorn hens

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Digestible lysine levels for laying hens and their effects on egg quality

Egg quality of semi-heavy laying hens fed on low protein diets (14.0% CP) and on different lysine levels is evaluated, while maintaining the same ratio of digestible amino acids / digestible lysine. Four hundred and twenty commercial strain Isa Brown laying hens, 28 weeks old, were divided into 42 experimental plots. A completely randomized design with six treatments and seven replicates was employed in four production cycles of 28 days each. Treatments comprised Control - 16.92% CP; 0.750% digestible lysine. Treatments 1 to 5, with CP levels 14% and digestible lysine levels 0.600, 0.675, 0.750, 0.825 and 0.900% respectively. Levels of Treatments 1 and 2 (0.546 and 0.640% digestible Met + Cys / 0.600 and 0.675% digestible lysine) provided smaller egg size. On the other hand, eggs had higher shell percentage when compared to control diet. When compared to other digestible amino acids, digestible lysine requirement may be estimated at 0.750% in a diet with 14% CP, which corresponds to the average daily intake of 876 mg dig. lysine hen-1 day-1 and 798 mg dig. Met + Cys hen-1 day-1, without jeopardizing performance and eggs' internal and external quality.

Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) in cotton: vertical distribution of egg masses, effects of adult density and plant age on oviposition behavior

O trabalho teve por objetivo determinar, em casa-de-vegetação, a densidade adequada de adultos, a idade ideal das plantas e a distribuição vertical de ovos nas diferentes partes da planta, visando à realização de estudos de resistência e à melhoria das práticas de manejo de Spodoptera frugiperda em algodoeiro. Os experimentos de oviposição de S. frugiperda em relação à densidade de adultos, relação entre plantas de algodoeiro e oviposição de S. frugiperda e não preferência para oviposição de S. frugiperda em variedades de algodoeiro foram realizados com plantas da variedade de algodoeiro BRS Ita 90. A não preferência (antixenose) para oviposição foi acompanhada nas variedades FiberMax 966, FiberMax 977, DeltaOpal, DeltaPenta, Acala 90, Coodetec 408, Coodetec 409, Coodetec 410, BRS Cedro, BRS Ipê, BRS Aroeira, IPR 96, IPR 20, BRS Araçá, IAC 24 e BRS Ita 90. Concluiu-se que S. frugiperda prefere ovipositar em plantas com cerca de 60 dias de idade, na superfície inferior das folhas situadas no terço superior dos testes de plantas sob condições de estufa. Uma densidade de, pelo menos, três pares de adultos S. frugiperda por planta foi suficiente para realizar testes de não preferência para oviposição em casa de vegetação. As variedades Coodetec 408, BRS Aroeira, BRS Araçá, BRS Ita 90 e DeltaPenta apresentaram resistência do tipo não preferência para oviposição de S. frugiperda. Em regiões com altas infestações de S. frugiperda, seria prudente para o cultivo utilizar a variedade de algodão BRS Ita 90.