Albumen Percentage Research Articles

The Effect of Calcium and Available Phosphorus Levels on Performance, Egg Quality and Bone Characteristics of Japanese Quails at End of the Egg-Production Phase

Calcium (Ca) and available phosphorus (avP) requirements for egg production are different between the beginning and the end of the egg-production cycle. The objective of this study was to estimate the Ca and avP requirements of Japanese quails at end of the production phase. In total, 256 Japanese quails with 48 weeks of age were randomly distributed in 2 x 2 factorial arrangement consisting of two Ca levels (29 and 38 g/kg) and two avP levels (1.5 and 3.0 g/kg), totaling four treatments with eight replicates of eight hens each. The variables evaluated were feed intake (FI); egg production (EP); marketable egg production (MEP); egg weight (EW); egg mass (EM); feed conversion ratio per egg mass (FCRM); feed conversion ratio per dozen eggs (FCRD); livability (L); yolk weight (YW), albumen weight (AW), eggshell weight (SW); yolk percentage (YP), albumen percentage (AP), eggshell percentage (SP), specific egg weight (SEW); bone calcium percentage (BCa), bone phosphorus percentage (BP), bone ash weight (Bash) and bone ash percentage (PBash). There was no interaction between Ca and avP levels for any of the evaluated parameters, except for SEW. Quail performance was not influenced by the treatments, except for MEP. Bone characteristics were not influenced by the tested dietary Ca and avP levels. However, SW and SP increased and AP decreased as dietary Ca level increased. The dietary supplementation of 38 g Ca/kg and 3.0 g avP/kg may increase marketable egg production and the egg quality of Japanese quails at end of the production cycle.

Order of amino acid inclusion in the diet of DeKalb White laying hens

Three hundred and twenty-four DeKalb White laying hens aged 42 weeks were distributed in a completely randomised design with nine treatments and six replicates of six birds in each treatment. The experiment lasted 112 days. Diets were: T1 = 16.02% crude protein - CP [Met + Lys + Thr + Trp + Val]; T2 = 14.02% CP [Met + Lys + Thr + Trp + Ile + Val]; T3 = 14.02% CP [no amino acid supplementation]; T4 = 14.02% CP [Met + Lys + Thr + Trp]; T5 = 14.02% CP [Met + Lys + Thr]; T6 = 14.02% CP [Met]; T7 = 14.02% CP [Lys]; T8 = 14.02% CP [Thr]; T9 = 14.02% CP [Trp]. Regarding the quality of the eggs, the percentage of yolk and albumen, shell thickness and Haugh unit were not affected by the different diets. The percentage of shell, specific gravity and albumen height showed significant differences. We found that supplementation of only one amino acid in the diet (T7, T8 or T9), with the exception of methionine (T6), worsened performance relative to the control. Supplementation of three amino acids (methionine, lysine and threonine; T5) or four amino acids (methionine, lysine, threonine and tryptophan; T4) worsened egg production and conversion per mass and per dozen eggs; however, feed intake and egg weight and mass were similar to the control treatment. When all amino acids (methionine, lysine, threonine, tryptophan, isoleucine and valine; T2) were supplemented performance was similar to the control treatment in all variables. Supplementation of methionine, lysine and threonine is essential for birds in the laying phase; however the addition of six essential amino acids (lysine, methionine, threonine, tryptophan, valine and isoleucine) to the diet of laying hens is important for a good productive performance comparable with the control treatment T1. However, the inclusion of the latter two (isoleucine and valine) is justified only if the production cost is lower.

Effect of feed grinding methods with and without expansion on prececal and total tract mineral digestibility as well as on interior and exterior egg quality in laying hens

The grinding of cereals by various milling methods as well as thermal treatment of feed may influence mineral digestibility and egg quality. The present study investigated the effect of feed produced by disc mill (D) and wedge-shaped disc mill (WSD), as mash (M) or expandate (E) on apparent ileal absorption (AIA) and apparent total digestibility (ATD) of calcium, phosphorus, magnesium, zinc, manganese, copper and iron, as well as on egg quality in laying hens. A total of 192 hens (Lohmann Brown) aged 19 wk, were assigned using a randomized design with a 2 × 2 factorial arrangement. Four experimental diets were offered ad libitum. Eggs were analyzed for weight, shape index, area, shell weight per unit surface area, yolk color, air cell, blood spot, Haugh unit, albumen and yolk measures (index, weight, height, width and length), shell measures (surface area, stability, density, thickness and membrane weight), as well as percent contents of albumen, yolk, shell, and shell membrane. The ATD for phosphorus, manganese, and copper was higher in WSD compared with D treatment (P = 0.028, P = 0.028 and P = 0.016, respectively). The interaction between milling methods and thermal treatment influenced ATD of copper (P = 0.033), which was higher in WSD+M group (41.0 ± 20.2) compared with D+E group (–3.21 ± 25.1), whereas no differences were observed for D+M (1.90 ± 37.8) and WSD+E (8.02 ± 36.2) groups. Egg stability tended to be higher in E compared with M treatment (P = 0.055). Albumen weight, percentage albumen weight, and albumen: yolk were higher and percentage yolk weight was lower in D compared with WSD treatment (P = 0.043, P = 0.027, P = 0.024, and P = 0.041, respectively). Number of blood spots was higher in E than M treatment (P = 0.053). In conclusion, use of a wedge-shaped disc mill resulted in higher ATD for phosphorus, manganese, and copper than use of a disc mill; however, digestibility for majority of minerals as well as egg quality parameters was comparable. Therefore, feed produced by either disc mill or wedge-shaped disc mill as mash or expandate may be used for laying hens without negative effects on egg quality.

Nutritional requirement of digestible threonine for brown-egg laying hens from 50 to 66 weeks of age

The dietary requirement of threonine was determined for brown laying hens in the period 50-66 weeks of age, based on performance parameters and quality of eggs. For this we used 150 laying Shaver Brown hens distributed in a completely randomized design with five treatments (0.460; 0.490; 0.520; 0.550 and 0.580%) of digestible threonine, six replications and five birds each. The digestible threonine levels did not affect (p>0.05) feed intake, egg production, egg weight, egg mass or feed conversion kg kg-1, but presented a quadratic effect (p<0.05) on feed conversion dozen kg -1, where the lower conversion was obtained with a supply of 0.521% threonine in the diet. There was no effect of dietary digestible threonine levels (p>0.05) on the yolk and albumen index, specific gravity, yolk percentage, thickness or shell weight per surface area, since the variable Haugh unit displayed linear behavior (p<0.05) and increased with increasing levels of dietary threonine. The percentage of albumen and shell presented a quadratic effect (p<0.05) according to the dietary levels of threonine, and the best levels of these variables were obtained with a supply of 0.520% and 0.521% digestible threonine in the diet. The dietary requirement of threonine for laying hens, aged between 50 and 66 weeks, based on converting food kg kg-1, percentage of albumen and shell is 0.521%

Exigência de lisina digestível para poedeiras semipesadas de 50 a 66 semanas de idade

Com o objetivo de determinar a exigência de lisina digestível para poedeiras semipesadas no período de 50 a 66 semanas de idade, foi realizado experimento utilizando-se 150 poedeiras Shaver Brown, distribuídas em delineamento inteiramente ao acaso, com cinco tratamentos (níveis de lisina digestível: 0,79; 0,82; 0,85; 0,88 e 0,91%), seis repetições e cinco aves por unidade experimental. Foram avaliados a produção de ovos, peso médio e a massa de ovos, consumo de ração e de lisina, conversão alimentar por massa e por dúzia de ovos, gravidade específica, unidade Haugh, o índice de gema e albúmen, porcentagem de albúmen, gema e casca. O consumo de ração, a conversão alimentar por massa e dúzia de ovos, a produção, o peso e a massa de ovos não foram influenciados (P>0,05) pelos níveis de lisina digestível. Houve aumento linear no consumo de lisina (P<0,01) com o incremento dos níveis desse aminoácido nas rações. As porcentagens de albúmen, gema e casca não foram influenciadas (P>0,05) pelos níveis de lisina digestível estudados. Os níveis de lisina influenciaram de forma quadrática (P>0,05) a unidade Haugh e o índice de albúmen, sendo estimados os níveis de 0,884 e 0,868% de lisina digestível, respectivamente. Para o índice de gema, a associação do modelo quadrático ao Linear Response Plateau (LRP) estimou o nível de 0,903% de lisina digestível. Quando o objetivo é maximizar a qualidade interna dos ovos, recomenda-se o nível dietético de 0,884%, 0,868% e 0,903% de lisina digestível para unidade Haugh, índice de albúmen e índice de gema, respectivamente.

<b>Internal quality of laying hen eggs fed on protease at different storage and stocking conditions

Effects on diets with reduction of crude protein and methionine + cystine (RCP) and protease supplementation (PRO) for laying hens at different ages and their influence on the internal quality of eggs at different conditions (STO) and storage times (TM) are evaluated. Four hundred and twenty eggs from commercial Hy-Line W36 laying hens collected at 32, 44 and 58 weeks of age were used. Experimental design was completely randomized in a factorial scheme 3 x 2 x 2 x 2: RCP (control, enhancement of one and two times the enzyme protease), PRO (with and without protease), STO (room temperature and refrigerated) and TM (14 and 28 days), with seven replications of one egg per experimental unit. The factorial scheme 3 x 2 x 2 was used at 58 weeks of age, because TM could not be evaluated. The percentages of egg weight loss, Haugh unit, albumen percentage, percentage and yolk index were evaluated after each storage time. RCP and PRO had no effect on internal egg quality whereas eggs under refrigeration preserved their internal quality regardless of the different storage periods.

Comparison of moulting methods for layers: high-zinc diet versus fasting

The serum biochemical profiles, thyroid hormones, body weights and the production and quality of eggs subsequent to moulting, were compared in laying hens subjected to conventional forced moulting or forced moulting with a diet high in zinc.A total of 200 Dekalb White laying hens in their second production cycle were studied. Blood sampling was conducted in a factorial experimental design (2 × 3) with two methods of moulting (fasting or zinc) and three sampling periods (pre-moult, moult and subsequent peak).Total egg protein content, including globulins, was greater with the zinc diet, whereas egg weight and albumen percentage were greater after fasting. The zinc method resulted in an increased shell thickness and calcium percentage but lower percentage of phosphorus. During the moulting period, the hens in the zinc group had heavier mean body weights.It was concluded that moulting with a high-zinc diet could replace fasting, without negative effects on body weight, biochemical variables or subsequent egg quality and production. The zinc method was also better for the birds’ welfare.

Nutritional requirement of available phosphorus for laying hens after 63 weeks of age

By presenting itself as the third most expensive nutrient rations, phosphorus addition to its economic importance has become an object not only be related to the growth rate, but also by its involvement in bone development, production and egg quality . Therefore, in order to demonstrate adequate levels of available phosphorus for laying hens with 63 weeks of age, we performed a study evaluating parameters such as egg weight, egg mass, laying percentage, feed conversion, to the gravity specific, yolk weight, albumen weight, shell weight, percentage of yolk, shell percentage and percentage of albumen. As well as percentage of ash, phosphorus and finally, the resistance to breakage of bones.

Effects of different vaccine combinations against Mycoplasma gallisepticum on the internal egg and eggshell characteristics of commercial layer chickens , ,

Live F-strain Mycoplasma gallisepticum (FMG) vaccines are presently being used to help control field-strain MG outbreaks. However, they may exert some adverse effects on egg production. Live strains of MG of lesser virulence as well as killed vaccines have little or no effect on egg production, but afford lower levels of protection. This has led to research investigating their use in combination with a subsequent overlay vaccination of FMG given later in the production cycle. In the present study, 2 trials were conducted to investigate the effects of prelay vaccinations of live and killed MG vaccines or their combination, in conjunction with an FMG vaccine overlay after peak production, on the egg characteristics of commercial layers. The following vaccination treatments were administered at 10 wk of age (woa): 1) unvaccinated (Control), 2) MG–Bacterin (MGBac) vaccine, 3) ts-11 strain MG (ts11MG) vaccine, and 4) MGBac and ts11MG combination (MGBac + ts11MG). At 45 woa, half of the birds were overlaid with an FMG vaccine. In each trial, internal egg and eggshell parameters including egg weight (EW), Haugh unit score (HU), eggshell breaking strength (EBS), percentage yolk weight (PYW), percentage albumen weight (PAW), percentage eggshell weight (PSW), eggshell weight per unit surface area (SWUSA), percentage yolk moisture (PYM), and percent total lipids (PYL) were determined at various time periods between 21 and 52 woa. At 28 woa, SWUSA was lower in the ts11MG and MGBac + ts11MG groups compared to the Control group. Conversely, at 43 woa, SWUSA was higher in the ts11MG than in the MGBac group. Between 23 and 43 woa, PYL was higher in the MGBac and ts11MG groups in comparison to the Control group. In conclusion, vaccination with MGBac alone or in combination with ts11MG at 10 woa with or without an FMG vaccine overlay at 45 woa does not adversely affect the internal egg or eggshell quality of commercial layers throughout lay.

Effect of sweet green pepper on yolk color and performance of laying hens

An experiment was conducted to evaluate the effects of sweet green pepper (SGP) on the performance and egg quality of commercial laying hens. A total of 144 Hy Line W36 egg layers were randomly assigned to 4 treatments with 9 replicate groups of 4 hens each. Treatments consisted of the following diets: 1) basal diet (BD), 2) BD + 75 ppm SGP, 3) BD + 125 ppm SGP, 4) BD + 225 ppm SGP. The diets contained 2,730 kcal/kg metabolizable energy and 15.5% crude protein. Egg production and egg quality were monitored for 16 weeks. Feed intake, hen-day egg production, egg mass, and feed conversion per dozen were not significantly affected by the addition of SGP to the diets. The addition of 225 ppm of SGP decreased egg weight. Specific gravity, albumen height, Haugh unit, yolk weight, albumen weight, albumen percentage, and yolk yellowness (b*) were not significantly affected by the addition of SGP. The addition of SGP to the diets increased yolk percentage, yolk color using a Roche fan, and yolk redness (a*). Based on these data, SGP was shown to be a useful feed ingredient for laying hens; it can be included in diets without negative effects on performance and egg quality. However, owing to the depression of egg weight with the inclusion of SGP, it may be of interest to producers and industry to control egg size in old layers and possibly improve shell quality. The addition of SGP to the diets impacted yolk color and may be useful in specialty markets.

Egg quality of hens fed different digestible lysine and arginine levels

This experiment aimed at evaluating the influence of the supplementation of digestible lysine and digestible arginine at different ratios in the diet fed to layers between 24 to 44 weeks of age on egg quality. In total,320 Lohmann LSL laying hens were allotted according to a completely randomized design in a 2 x 4factorial arrangement, consisting of two digestible lysine levels (700 or 900 mg/kg of diet) and four digestible arginine levels (700, 800, 900,or 1000 mg/kg of diet). Diets contained, therefore, digestible Lys:Arg ratios of 100, 114, 128, and 142 when the diet contained 700 mg digestible lysine per kg of diet, and 78, 89, 100, and 111 when 900 mg digestible lysine per kg was supplemented. The data obtained with digestible arginine levels were fitted to polynomial regression equations, and with digestible lysine, the F test (5% probability) was used to compare the means. The following variables were evaluated: egg weight; internal egg quality (yolk percentage and index, albumen percentage, Haugh units), eggshell quality (specific gravity andeggshell percentage); and whole egg, albumen, and yolk solids content. Digestible lysine and arginine interaction did not affect egg quality. Increasing levels of digestible lysine and arginine reduced eggshell quality and albumen solids, respectively. The levels of these amino acids suggested to improveegg quality are 700 mg digestible lysine and 700 mg digestible arginine/kg of feed at a Dig Lys: Dig Arg ratio of 100.

Utilização de farinha de casca de ovos em dietas para codornizes japonesas na fase de 11 a 25 semanas de idade

It was verified the possibility of replacement of limestone (CC) per quail eggshell meal (QSEM) in them diets in the phase of 11-25 weeks of age. It was used 192 Japanese quail (Coturnix coturnix japonica), distributed in a completely randomized design, consisting of three treatments (64 birds for treatment): Treatment 1: it was used 100% CC; Treatment 2: 50% of QESM + 50% CC and Treatment 3: 100% QESM. The parameters studied were: feed intake, egg production per bird-day, commercial egg production, egg weight, egg mass, feed conversion ratio per egg mass and per dozen eggs, shell thickness, specific weight, weights and percentages of yolk, albumen and shell. There was not significant effect when replacing 50% or 100 % of CC per QESM in feed intake, egg production per bird-day, commercial egg production, weight of yolk, percentages of yolk, albumen and shell, shell thickness and specific weight. However, there was significant effect: egg weight, egg mass, feed conversion ratios per egg mass and per dozen eggs and the weights of albumen and shell. It is concluded that the CC can be substituted by up to 100% QESM in diets for Japanese quails, in 11-25 weeks of age, without any reduction in productive performance.

The effect of milling method, thermal treatment, and particle size of feed on exterior and interior egg quality in laying hens

Summary Various milling methods, thermal treatment and particle sizes are used in feed production for laying hens, which may influence egg quality. The present study was designed to investigate the effect of feed produced by roller (R) and hammer mill (H) as mash (M) and expandate (E) with coarse (C) and fine (F) particle size on exterior and interior egg quality in layers. A total of 240 hens (Lohmann Brown), 19 weeks old, were used in a randomized design with 2×2×2 factorial arrangement. Eight experimental diets were offered ad libitum during the whole experimental period and one week before for diet adaption. Eggs were analyzed for egg weight, area, shape index, shell weight per unit surface area, air cell, yolk color, blood spot, Haugh unit, yolk and albumen measures (weight, index, height, width and length) shell measures (stability, surface area, density, thickness and membrane weight), and percent contents of yolk, albumen, shell and shell membrane. The shell membrane weight and percent shell membrane weight was lower in treatment H as compared to treatment R ( P<Â 0.01 and P≤0.01, respectively). Thermal treatments displayed higher percent shell membrane weight in treatment E than treatment M ( P≤0.04). The shell density was higher in treatment F in comparison with treatment C ( P≤0.04). The shell thickness and shell weight were higher in treatment C as compared to treatment F ( P≤0.02 and P≤0.04, respectively). The interaction between milling methods and particle size affected shell thickness ( P≤0.01). Milling method influenced yolk index and yolk height, which were higher in treatment H as compared to treatment R ( P<Â 0.01 and P≤0.02, respectively). The albumen height was higher in treatment C than treatment F ( P≤0.03). The interaction between milling method and particle size affected blood spot, albumen length and yolk height ( P≤0.05, P≤0.04 and P≤0.04, respectively). The interaction between thermal treatments and particle size affected yolk color ( P≤0.04). Additionally, percent albumen weight was affected by interaction between milling methods, thermal treatments and particle size ( P≤0.05). In conclusion, most of egg quality parameters of economic importance were not affected by the treatments used in present study. Therefore, milling method, thermal treatment and particle size of feed seem to be of lower importance for layer feed production regarding the optimized egg quality.

&lt;b&gt;Digestible lysine levels for brown layers

This study was carried out to evaluate the effects of different digestible dietary lysine levels on performance and egg quality characteristics, from 25 to 41 weeks of age. One hundred twenty Hy-Line Brown layers were randomly distributed in five treatments with six replications of four birds each, totaling 30 experimental units. Experimental diets were based on corn and soybean meal, were isocaloric and isonutrient, with differences only in lysine levels (0.70, 0.75, 0.80, 0.85, and 0.90%). The study evaluated feed intake, lysine intake, energy consumption, egg production, egg weight, egg mass, and feed conversion. Internal egg quality was evaluated by Haugh unit, the percentages of yolk and albumen percentage, while external quality was measured by specific gravity, eggshell thickness and shell percentage. It was concluded that the level of 0.70% of digestible lysine or the intake of 708 mg bird-1 day-1 for Hy-Line Brown layers from 25 to 41 weeks of age can be enough to express the genetic potential.

&lt;b&gt;Whole rice in japanese quails’ diet

A trial was conducted to evaluate the use of dehulled and unpolished whole rice in Japanese quails' diet. A total of 100 80-days-old Japanese quails (149.07 ± 10 g) were distributed in five treatments: 0% dehulled and unpolished whole rice (control diet based on corn and soybean meal), 20, 40, 60, and 80% of whole rice in replacement of corn; respectively, treatments 1, 2, 3, 4, and 5. Productive performance was evaluated through egg production (%), egg weight (g), body weight (g), egg mass (g), feed conversion per egg mass and feed conversion per dozen eggs. The following variables measured the internal quality of eggs: albumen height (mm), yolk color and percentage, egg white percentage and Haugh units. The external quality of eggs was measured through specific gravity (g cm-3), shell thickness (µm) and shell percentage. Treatment means were analyzed through polynomial regression at 5%. As the level of whole rice was increased in the diets, a significant linear increase in egg production (p = 0.005), egg mass (p = 0.007), shell thickness (p = 0.03) and specific gravity (p = 0.007) was observed. Feed conversion per egg mass (p = 0.006), feed conversion per dozen eggs (p = 0.003) and egg color (p < 0.0001), on the other hand, were reduced linearly. The increased utilization of whole rice increased the cost of the diet. In conclusion, the addition of dehulled and unpolished whole rice in partial substitution of corn in Japanese quails' diets increases the egg production and reduces the yolk color.

Vplyv rastlinných silíc na parametre a mikrobiologickú kvalitu vnútorného obsahu vajec nosníc

Essential oils are aromatic oily liquids obtained from plant material (flowers, buds, seeds, leaves, twigs, bark, herbs, wood, fruits and roots). Besides antibacterial properties, essential oils or their components have been shown to exhibit antiviral, antimycotic, antitoxigenic, antiparasitic, and insecticidal properties. In this experiment the effects of supplementation of the diet for laying hens with thyme and hyssop essential oils on physical and microbiological egg parameters were studied. Hens of laying hybrid ISA Brown (n = 72) were randomly divided at the day of hatching into 3 groups (n = 26) and fed for 41 weeks on diets which differed in kind of essential oil supplemented. In the first ex­pe­ri­men­tal group the feed mixture was supplemented with thyme essential oil addition 0.25ml . kg−1, in the second one got hyssop essential oil the same dose of 0.25ml . kg−1. The results suggest that the supplementation of thyme essential oil into laying hens diet statistically significantly increased egg albumen weight, egg albumen percentage portion (P &lt; 0.05) and egg yolk colour (9.07a, 9.47b, 9.06a; P &lt; 0.01), compared to the control group and decreased egg yolk percentage ratio. However, the most of qualitative parameters of internal content egg were not with thyme and hyssop essential oils addition significantly influenced. Significant differences in microbiological indicators were found among coliforms bacteria, enterococci, total number count (P &lt; 0.001), lactobacilli and mesophilic sporulating aerobes bacteria (P &lt; 0.05).

Exigência nutricional de proteína bruta para codornas japonesas (Coturnix coturnix japonica) na fase de postura

O objetivo do trabalho foi determinar o melhor nível de proteína bruta na alimentação de codornas japonesas em fase de produção. Foram utilizadas 300 codornas com 16 semanas de idade, alojadas em gaiolas, em um delineamento inteiramente casualizado, com cinco tratamentos, seis repetições e dez aves por unidade experimental. Os níveis avaliados foram 14, 17, 20, 23 e 26% de proteína bruta, e as dietas foram formuladas para serem isoenergéticas. Foi verificado efeito quadrático para consumo de ração, peso de ovo, massa de ovo, ingestão de energia, eficiência energética por dúzia de ovo, coeficiente de digestibilidade de nitrogênio, retenção de nitrogênio, peso de gema, casca e albúmen. Efeito linear foi verificado para produção de ovos, ingestão de proteína, conversão alimentar por massa de ovos, eficiência energética por massa de ovo em kg, peso final e gravidade específica. Não houve efeito significativo para conversão alimentar por dúzia e concentração sérica de ácido úrico. Recomenda-se nível de 20% de proteína bruta para codornas japonesas em fase de postura.

Yolk sac fatty acid composition, yolk absorption, embryo development, and chick quality during incubation in eggs from young and old broiler breeders

The objective of the present study was to examine the changes in yolk and yolk sac fatty acid composition and also to investigate egg content, yolk absorption, embryo development during incubation, and chick quality at hatch in eggs from 36- and 52-wk-old broiler breeders. The fatty acid profiles of the yolk, the yolk sac of embryos, and the residual yolk sac of chicks were analyzed before incubation, on d 18, and at hatch, respectively. Yolk sac weight, and embryo weight and length were measured on d 18, and chick weight and length were measured at hatch. Egg weight, yolk and albumen weight, yolk percentage, and yolk:albumen ratio increased as breeder age increased, but the albumen percentage decreased. Yolk absorption in absolute value (g) was higher in embryos from the old flock on d 18 and at hatch. Relative yolk absorption was similar between age groups on d 18, whereas it was higher in the young flock at hatch. Breeder age affected the yolk sac weight and was higher in the old flock during incubation. Embryo or chick weight and length, and yolk-free BW were affected by breeder age during incubation. These parameters were higher in the old flock with a difference of 3.7 g, 0.8 cm, and 2.6 g, respectively, on d 18 and 7.4 g, 1.4 cm, and 6.3 g, respectively, at hatch compared with the young flock. The effect of breeder age on fatty acid composition differed significantly by sampling day. Palmitic, stearic, oleic, and linoleic acids were major fatty acids in the fresh yolk, ranging from 13.02 to 29.24%. These were followed by palmitoleic and arachidonic acids ranging from 1.24 to 7.04%, with the remaining fatty acids below 1%. Higher concentrations of myristic, palmitoleic, and oleic acids and lower concentrations of heptadeconoic, stearic, linoleic, and arachidonic acids were found in the residual yolk sac of the young flock than the old flock. The results showed preferentially selective absorption of some fatty acids by the embryo during incubation.

&lt;b&gt;Carbohydrase and phytase supplementation in diets for semi-heavy laying hens

This study was conducted in order to evaluate the association of phytase with an enzymatic complex comprised of carbohydrases (α-galactosidase, galactomannan, xylanase and β-glucanase) in nutrition reduction diets for semi-heavy laying hens and its effect on egg performance and egg quality. Four hundred Isa Brown laying hens with 42 to 57 weeks of age were distributed in an entirely random experiment with five treatments and 8 repetitions, during five production periods of 21 days. Variables studied: egg production, feed intake, mean egg weight, feed conversion, Haugh unit, percentage of yolk, egg white and albumen, yolk color, eggshell thickness and specific gravity. There was a significant interaction (p &lt; 0.05) between treatments and experimental periods for feed intake. There were no significant effects (p &gt; 0.05) of treatment on production, egg weight or internal and external egg quality. Treatment effects on feed conversion showed better values for hens fed with the control diet. The levels of nutrient reduction used in the diets with or without enzyme supplementation did not provide good results with regard to feed conversion and feed intake. However, they did not affect the other parameters for egg production and internal and external egg quality.

Lisina digestível em poedeiras semipesadas

This study was carried out to evaluate the effects of different digestible dietary lysine levels on performance and egg quality characteristics, from 25 to 41 weeks of age. One hundred twenty Hy-Line Brown layers were randomly distributed in five treatments with six replications of four birds each, totaling 30 experimental units. Experimental diets were based on corn and soybean meal, were isocaloric and isonutrient, with differences only in lysine levels (0.70, 0.75, 0.80, 0.85, and 0.90%). The study evaluated feed intake, lysine intake, energy consumption, egg production, egg weight, egg mass, and feed conversion. Internal egg quality was evaluated by Haugh unit, the percentages of yolk and albumen percentage, while external quality was measured by specific gravity, eggshell thickness and shell percentage. It was concluded that the level of 0.70% of digestible lysine or the intake of 708 mg bird-1 day-1 for Hy-Line Brown layers from 25 to 41 weeks of age can be enough to express the genetic potential.