Cold Drinking Water Boosts the Cellular and Humoral Immunity in Heat-Exposed Laying Hens

Area of Science:

• Animal Science
• Immunology
• Poultry Science

Background:

• Heat stress negatively impacts poultry productivity and immunity.
• Laying hens are susceptible to heat stress, leading to reduced feed intake and egg production.
• Maintaining optimal immune function is crucial for poultry health and productivity under heat stress.

Purpose of the Study:

• To investigate the effects of cold drinking water on cellular and humoral immunity in heat-exposed laying hens.
• To evaluate the impact of cold water on feed consumption, egg production, and immune parameters.
• To determine if cold water can mitigate the negative effects of heat stress on laying hens.

Main Methods:

• One hundred and eight laying hens were divided into three groups: thermoneutral with normal water, heat-stressed with normal water, and heat-stressed with cold water (15°C).
• Hens were exposed to high ambient temperature (35°C) for 8 hours daily for four weeks.
• Feed intake, egg production, egg weight, feed conversion ratio, and blood immune parameters (cell counts, cytokine mRNA expression, immunoglobulin levels) were measured.

Main Results:

• Cold drinking water significantly improved feed intake and egg production in heat-stressed hens.
• Egg weight and feed conversion ratio were not significantly affected by cold water treatment.
• Cold water restored peripheral blood mononuclear cell counts (B-cells, T-cells), normalized helper/cytotoxic T-cell ratios, and increased mRNA expression of IL-2 and IFN-γ.
• Plasma concentrations of IL-2, IFN-γ, and immunoglobulin G were significantly recovered by cold water treatment.

Conclusions:

• Cold drinking water is an effective strategy to mitigate the adverse effects of heat stress on laying hen productivity.
• Cold water enhances heat dissipation, leading to improved feed intake and egg production.
• Cold drinking water significantly boosts cellular and humoral immunity in heat-stressed laying hens, supporting overall health and resilience.