The present study investigated the effect of different ambient temperature and relative humidity (RH) but equal temperature-humidity index (THI) on laying performance, egg quality, heterophil to lymphocyte ratio (H/L ratio), corticosterone (CORT) concentration in blood, yolk and albumen, and plasma biochemical parameters in laying hens. One hundred and twenty commercial hens (Hy-Line Brown) aged 60 weeks were allocated into 2 environmental chambers. Laying hens were subjected to either one of two thermal treatments, i.e., 26ºC and 70% RH (LH75) and 30ºC and 30% RH (HL75) for 28 days. Both thermal treatments had equal THI being 75. Neither LH75 nor HL75 affected (P > 0.05) laying performance including egg production, egg weight, egg mass, feed intake, and feed conversion ratio. Plasma biochemical parameters such as total cholesterol, high-density lipoprotein cholesterol, triglyceride, calcium, magnesium, and phosphorus was not altered (P > 0.05) by thermal treatments. As to the stress indicators, both environment regimes failed (P > 0.05) to affect blood H/L ratio and CORT levels in plasma, yolk and albumen although albumen CORT levels were elevated (P < 0.05) in LH75 vs. HL75 at days 3, 7, and 28. In conclusion, our study suggests that laying hens performed and responded equally when they were exposed to equal THI environment conditioned from either 26ºC and 70% RH or 30ºC and 30% RH. The results of this study will be served as a scientific basis for management decisions and handling under thermally challenging conditions.
We investigated the effect of different ambient temperatures and relative humidity (RH) with the same temperature-humidity indices (THI) on laying performance, egg quality, heterophil to lymphocyte ratio (H/L ratio), corticosterone (CORT) concentration in blood, yolk, and albumen, and plasma biochemical parameters of laying hens. Commercial hens (Hy-Line Brown; n = 120), aged 60 weeks, were allocated to two environmental chambers. Laying hens were subjected to either one of two thermal treatments—26 °C and 70% RH (TLHH75) or 30 °C and 30% RH (THHL75) for 28 days—with the same THI of 75. Neither TLHH75 nor THHL75 affected laying performance, including egg production, egg weight, egg mass, feed intake, and feed conversion ratio (p > 0.05). Plasma biochemical parameters such as total cholesterol, high-density lipoprotein cholesterol, triglycerides, calcium, magnesium, and phosphorus were not altered by the environmental treatments (p > 0.05). As for stress indicators, both environmental regimes failed to affect blood H/L ratio and CORT levels in plasma, yolk, and albumen (p > 0.05), although albumen CORT levels were elevated (p < 0.05) in TLHH75 group at day 7. Hence, our study suggests that laying hens performed and responded similarly when exposed to either TLHH75 or THHL75 characterized by the same THI. These results can serve as a scientific basis for management decisions and handling laying hens under thermally challenging conditions.
Alternative growth promoters are able to not only effectively replace the traditional use of antibiotics but also provide additional health benefits for livestock and reduce food safety concerns. This study investigated the effects of dry Hydrastis canadensis on the laying performance and fecal microbial community of laying hens. Twenty-four Lohmann (LSL, white layer strain) hens were reared from 40 to 48 weeks of age and randomly allotted to four dietary treatments (six birds/treatment). The dietary treatments comprised a basal diet with no treatment as control, a basal diet plus 0.6% powder of dry Hydrastis canadensis roots (R) or leaves (L), and a basal diet plus 0.6% powder of a mixture of dry Hydrastis canadensis roots and leaves (1:1, LR). No mortality was observed in the whole experimental period. The results indicated that albumen height in the LR group was significantly greater than that in the control group. The diet supplemented with Hydrastis canadensis had no significant effects on egg production rate, egg weight, eggshell strength, eggshell thickness, Haugh unit, or yolk height during the whole experimental phase. However, principal coordinate analysis, comparative heat map analysis, and cluster dendrogram analysis of cecal microbiota showed distinct clusters among the groups treated with Hydrastis canadensis and the control group. Regarding blood biochemical parameters, serum cholesterol levels were significantly lower in all Hydrastis canadensis-treated groups compared with those in the control group. Moreover, serum low-density lipoprotein levels were lower in hens supplemented with the leaf of Hydrastis canadensis. The abundances of the phyla Fusobacteria and Kiritimatiellaeota were increased (p < 0.05) in laying hens fed with 0.6% Hydrastis canadensis leaves, whereas the abundance of the phylum Firmicutes in cecum digesta decreased in response to treatment with Hydrastis canadensis roots and leaves. The relative abundance of the Fusobacterium genus was higher in the LR group compared with that in the control. On the contrary, we found a different trend in the Synergistes genus. The potential influences of these microbiota on the performance of laying hens were discussed. The results demonstrate that Hydrastis canadensis can improve the egg albumen height and modulate the cecum digesta microbiota composition of laying hens.
This study aimed to evaluate the increasing levels (0, 1, 2, 3 e 4%) of fish by-product meal in diets for laying hens on performance, egg quality and economic analysis. A total of 160 Dekalb White hens with 52-wk old were distributed in a completely randomized design with five treatments and four replicates of eight birds each. The experiment lasted 84 days divided into four periods of 21 days. Estimates of fish by-product meal levels were determined by polynomial regression. Differences (p < 0.05) were detected for all variables of performance, in egg weight, yolk and albumen percentage, yolk and albumen height, feed cost and production cost, in which the inclusion of fish by-product meal in the diets showed better results. It can be concluded that fish by-product meal can be used in diets for hens as alternative feed, with better results in egg production, feed conversion, egg weight, yolk-albumen ratio and a reduction in feed cost and production cost.
This study was conducted to appraise the effects on egg quality and production performance of laying hens when drinking water was supplemented with calcium (Ca) and magnesium (Mg). A total of 384 (64-week-old) Hy-line Brown laying hens were assigned at random to four treatments, which consisted of CON: unsupplemented drinking water; T1: drinking water + 2 mg/L Ca + 250 mg/L Mg; T2: drinking water + 4 mg/L Ca + 510 mg/L Mg /10 L; and T3: drinking water + 5 mg/L Ca and 760 mg/L Mg. The experiment lasted six weeks. Water intake increased linearly in week 1 with the rising levels of Ca and Mg in the drinking water. Increasing the Ca and Mg levels improved eggshell strength (week 2 (P =0.01), week 5 (P =0.01), and week 6 (P = 0.03), and eggshell thickness (week 6) (P =0.02) and reduced the rate at which eggs were broken (week 4) (P =0.01). The supplemental Ca and Mg did not affect egg production, egg weight, Haugh unit, albumen height, eggshell colour, and yolk colour compared with CON. Nor did they influence the Haugh unit and albumen height after storing for 1, 5, 10 and 15 days. In conclusion, adding Ca and Mg to the drinking water increased the thickness and strength of the eggshells.
Twenty groups of 36 laying hens in individual cages were fed on one of 5 diets in which the energy:protein ratio was constant. Diets 1 to 5 had crude protein 12.0, 12.9, 14.0, 15.0 and 16.0% and metabolizable energy 8.71, 9.57, 10.27, 11.10 and 11.70 MJ/kg. From 24 to 64 weeks old, egg production of hens given diets 1 to 5 was 71.46, 71.31, 72.51, 71.13 and 69.99%, respectively. Corresponding values of mean egg weight, weekly feed intake and efficiency of feed conversion were 60.51, 60.47, 61.11, 61.02, 61.07 g; 157.16, 147.56, 142.03, 130.37, 126.72 g; 3.674, 3.460, 3.262, 3.031, 3.014 kg feed/kg egg, respectively. (Abstract retrieved from CAB Abstracts by CABI’s permission)
High Temperature With Low Humidity or Vice Versa Does Not Affect Performance and Physiology of Laying Hens