Abstract: The objective of this research was to determine the effects on laying performance, egg quality and serum hormone levels, of feeding fresh Fagopyrum dibotrys as part of the diet of Changshun Blue-Eggshell laying hens. Laying hens (n=300) were divided into five treatment groups with a completely randomized design: Control (group C, basic diet), T₁ (basic diet+5% F. dibotrys), T₂ (basic diet+10% F. dibotrys), T₃ (basic diet+15% F. dibotrys) and T₄ (basic diet+20% F. dibotrys), with 5 replicates per treatment and 12 chickens per replicate. All experimental laying hens were exposed to (31.4±1.5) ℃ to induce natural heat stress. Data collected included: The average monthly feed intake, egg weight and number of the laying eggs, the apparent quality of eggs, the content of amino acids and fatty acids in the whole egg, the levels of serum hormones, inflammatory factors and endotoxin concentration at the end of the experiment. It was found that: 1) The laying rate of the T₁ group in the second month was significantly higher than that of other groups (P<0.05), and there was no significant difference between the laying rates of groups C, T₁ and T₂ in the third month and the whole period (P>0.05). 2) The egg content of isoleucine was the highest in T₃ group, but higher in T₃ and T₄ groups than the others (P<0.05), but the polyunsaturated fatty acids in group C were significantly higher than those in other treatment groups (P<0.05). 3) The concentrations of adrenocorticotropic hormone and corticosterone in group C were significantly higher than those in the experimental groups (P<0.05); conversely, the levels of corticosterone and luteinizing hormone in group C were significantly lower than those in the experimental group (P<0.05), and the levels of IL-6, tumor necrosis factor α and serum endotoxin in the experimental group were significantly lower than those in the control group (P<0.05). Thus, it was found that adding 10% F. dibotrys to the diet had no negative effect on the average egg production rate, deepened the yolk color, improved the amino acid composition and content of the whole egg, but had a negative effect on the fatty acid composition of the yolk, increased the serum FSH and LH content, and reduced the serum inflammatory factor and endotoxin level.

Key words: Fagopyrum dibotrys, heat stress, performance, Changshun Blue-Eggshell laying hen