A problem with characteristics of the thin albumen in laying hens

Influence of the energy concentration and the standardized ileal digestible lysine content of the diet on performance and egg quality of brown-egg laying hens from 18 to 41 weeks of age

The influence of the energy and the standardized ileal digestible lysine (DLys) content of the diet on egg production and egg quality, was studied in brown-egg laying hens from 18 to 41 wk of age. The experimental design was completely randomized with 10 treatments organized as a 2 × 5 factorial with 2 energy concentrations (2,750 and 2,800 kcal AMEn/kg) and 5 levels of DLys (values varied from 0.66 to 0.78% and 0.67 to 0.79%, for the low and high energy diets, respectively). Each treatment was replicated 10 times (10 hens per replicate). The data were analyzed using the MIXED procedure of SAS with energy concentration and DLys content of the diets as main effects. In addition, the effects of the DLys on the variables studied were partitioned into its lineal and quadratic components. From 18 to 21 wk of age (pre-peak phase), diet composition had limited effects on egg production. From 22 to 41 wk of age (peak phase), however, an increase of 50 kcal AMEn/kg diet increased egg weight (P < 0.05) and tended to improve energy intake (P = 0.083) and feed conversion ratio (P = 0.074). An increase in DLys improved linearly (P < 0.001) egg production, egg weight, egg mass, feed conversion, and energy conversion ratio, and tended to increase BW gain (P = 0.074). Diet composition did not any affect egg quality trait except shell strength that increased linearly (P < 0.05) with increases in the DLys. Cumulatively (18–41 wk of age), egg weight increased (P < 0.05) as the energy and the DLys content of the diet increased. In summary, an increase in energy and DLys content of the diet had limited effects on egg production during the prepeak phase but improved egg production, feed conversion ratio, and BW gain during the peak phase. The data indicate that hens require at least 839 mg DLys/d to maximize egg production in the peak production phase.

Effect of dietary supplementation of Bacillus subtilis DSM29784 on hen performance, egg quality indices, and apparent retention of dietary components in laying hens from 19 to 48 weeks of age

The aim of the current study was to evaluate egg production, quality, and apparent retention (AR) of components in response to a multi-dose application of a single strain Bacillus subtilis (SSB; DSM29784) in a corn-soybean meal basal diet fed to hens (19 to 48 wk of age). The treatments consisted of a basal diet with either no probiotic (control, CON), 1.1E+08 (low, LSSB), 2.2E+08 (medium, MSSB) or 1.1E+09 (high, HSSB) CFU/kg of diet. A total of 336, 19-wk old Shaver White layers were used at a stocking density of 7 and 6 hens/replicate-cage in layer I (week-19 to 28) and layer II (week-29 to 48) phases, respectively. Evaluated variables included feed intake (FI), body weight (BW), feed conversion ratio (FCR), egg production, weight, mass, and egg quality (shell thickness, shell breaking strength, albumen height (AH), and Haugh unit (HU)). Excreta was collected at the end of week-28 for AR of components and apparent metabolizable energy (AME). Supplementation of SSB increased (P = 0.008) FI during peak egg-lay (week-24) and BW increased linearly (P = 0.019) in early layer II (week-32). In layer I, LSSB compared with CON increased EM (g/egg) by 3.3% (P = 0.049). In layer II, SSB inclusion tended to improve FCR (linear, P = 0.094; g FI: g EM). Although shell breaking strength was lowest at week-20 with HSSB (4.518 vs. 4.889 kgf for HSSB vs. CON; P = 0.045), AH and HU were improved at higher dose of SSB, in both phases (P ≤ 0.005). Apparent retention of dry matter, AME, and minerals were improved (P < 0.0001) in a dose response. Hence, while the low dose of B. subtilis DSM29784 improved hen performance and maintained egg quality in both phases, a higher dose of SSB improved the interior protein quality of eggs (AH and HU).

Genetic parameters and characterization of egg content spreading area in White Leghorn chickens

Uncharacteristically large spreading area on a flat surface of broken egg negatively affects egg quality assessment and reduces eggs' economic value. In this study, we investigated the heredity of the egg content spreading area as well as the relationships between the egg content spreading area and egg quality traits and properties. We measured the total egg content spreading area (TECA), outer thin albumen area (OTAA), inner thick albumen area (ITAA), yolk area (YA), and egg quality traits for 1414 newly laid eggs from 487 27-wk-old White Leghorn pure line pullets. The genetic parameters of egg content spreading areas were estimated. The phenotypic and genetic correlations between egg content spreading area and egg quality traits were analyzed. The differences in the properties of eggs with similar egg weight but markedly different TECA were also analyzed. The heritability estimates for TECA, OTAA, ITAA, and YA were low to moderate, with values of 0.214, 0.176, 0.340, and 0.280, respectively. Egg weight was related to TECA with a phenotypic correlation of 0.450 (P < 0.01) and a genetic correlation of 0.349. A high genetic correlation (-0.731) was found between TECA and Haugh unit. In eggs with larger TECA, the weight and total solid content of outer thin albumen (OTA) and moisture content of inner thick albumen (ITA) were significantly higher, whereas the weight and total solid content of ITA was markedly lower, but no differences (P > 0.05) were found in the pH of OTA and ITA, moisture content of OTA, as well as the eggshell strength, thickness, and non-destruction and fracture deformation between eggs with similar egg weight but markedly different TECA. These results suggest that the egg content spreading area can be regulated via the direct selection strategy or indirect selection of the ratio of OTA to ITA in the breeding program.

Effect of dietary threonine on laying performance and intestinal immunity of laying hens fed low-crude-protein diets during the peak production period

Threonine (Thr) may be a limiting amino acid for laying hens fed diets with lowered protein level. An experiment was conducted to examine laying performance, and the intestinal immune function of laying hens provided diets varying in digestible Thr levels. Lohmann Brown laying hens (n = 480), 28 weeks of age, were allocated to six dietary treatments, each of which included five replicates of 16 hens. Dietary crude protein (CP) 16.18% diet was offered as the positive control diet. L-Thr was added to the negative diet (14.16% CP) by 0, 1.0, 2.0, 3.0 and 4.0 g/kg, corresponding 0.44%, 0.43%, 0.49%, 0.57%, 0.66% and 0.74% digestible Thr. At 40 weeks, a reduction in CP level decreased laying performance (p < 0.05). In the low CP, increasing dietary Thr increased (p < 0.05) egg production and egg mass and rose to a plateau between 0.57% and 0.66%. The hens fed 0.66% Thr showed the lowest value (p < 0.05) of feed conversion ratio (FCR). Serum level of uric acid showed the lowest values (p < 0.05) at 0.57-0.66%. In addition, serum-free Thr maximized (p < 0.05) between 0.66% and 0.74%. Digestive trypsin activity decreased (p < 0.05) when hens fed the low-CP diet compared with hens fed CP (16.18%) and hens fed 0.57-0.66%. Expressions of ileal MUC2 mRNA maximized (p < 0.05) at 0.66% Thr. Occludin mRNA increased with increasing Thr level (p < 0.05). sIgA mRNA reached to the maximum level (p < 0.05) at 0.66% and 0.74% Thr. INF-γ mRNA reached to the lowest level (p < 0.05) at 0.65%. Expressions of ileal IL-2, IL-6, IL-1β mRNA decreased with increasing Thr level (p < 0.05). In conclusion, Thr supplementation resulting in optimal laying performance and stimulated the mucosal immune system, suggesting that it is a limiting amino acid in the low-crude-protein diet of laying hens during the peak production period.

Comparison of quality attributes of shell eggs subjected to directional microwave technology

Microwaves have been shown to cause thermal as well as nonthermal destruction of pathogens such as Salmonella, which can be found in shell eggs. The objective of this study was to determine if using microwave technology would cause detrimental quality effects in shell eggs. Treatments included control (no treatment) and microwave-treated (20 s) shell eggs. There were no differences in mineral content, fatty acid profile, Haugh units, broken-out score, yolk index, emulsion stability, pH of whole egg, and foaming capacity between 2 treatments (P >or= 0.05). At 0 and 30 d, there were no noticeable differences in H(2)O activity between 2 treatments. The foaming stability and albumen thermocoagulation of microwave-treated eggs were significantly higher than control eggs (P <or= 0.05). The control eggs had significantly higher emulsion capacity and lower vitelline membrane strength than the microwave-treated eggs (P <or= 0.05). Poached eggs were evaluated by sensory testing for hardness, yolk color, and albumen color, and there are no noticeable differences at 0, 15, or 30 d. At 0 d, the color of control albumen was more yellow than the microwave-treated albumen, and the chalazae of the microwave-treated eggs was more attached than the control eggs (P <or= 0.05). The TBA reactive substances were similar for 2 treatments at 0, 15, and 30 d. Peroxide values were significantly higher in the microwave-treated eggs at d 0 (P <or= 0.05), but at 15 and 30 d, no prominent differences in peroxide values were noted (P >or= 0.05). Therefore, microwave technology can be applied to shell eggs without causing detrimental effects to quality.

The Effect of Dietary Protein Level and Total Sulfur Amino Acid:Lysine Ratio on Egg Production Parameters and Egg Yield in Hy-Line W-98 Hens

A 3 x 3 treatment arrangement varying in dietary protein and TSAA:Lys was used to evaluate the effect of low-protein diets fed to Hy-Line W-98 laying hens. Phase I was 20 to 43 wk of age with 18.9, 17.0, and 14.4 g of protein/hen per day and 0.97, 0.85, and 0.82 TSAA:Lys, whereas phase II was 44 to 63 wk of age with 16.3, 14.6, and 13.8 g of protein/hen per day and 0.92, 0.82, and 0.72 TSAA:Lys. Egg production and feed consumption decreased from 83.7 to 82.2% and 98.8 to 95.6 g, respectively. Feed efficiency improved from 1.680 to 1.645 g of feed/g of egg mass with decreasing dietary protein. Body weight gain was similar for hens fed high or medium protein diets. In phase II, hens consuming 13.8 g of protein/day had significantly reduced egg weight compared with hens consuming 14.6 or 16.3 g of protein/day. Wet and dry albumen percentage, albumen solids, and albumen and yolk protein percentages were significantly decreased with feeding low-protein diets. Yolk protein percentage was increased from 14.85 to 15.11% when decreasing the ratio from 0.97 to 0.82. Hens consuming a low-protein diet produced eggs with the lowest specific gravity. An interaction was observed for protein retention during phase I, feeding 14.4 g of protein/day or a ratio of 0.97 improved protein retention by 9 and 16%, respectively. Overall, hens consuming 16.3 or 14.6 g of protein/hen per day performed similar to hens consuming 18.9 and 17.0 g of protein/hen per day during P1 and P2, respectively. Also, hens consuming diets containing 0.97 and 0.92 TSAA:Lys produced eggs with improved shell quality as compared with other ratios during P1 and P2, respectively.