Effects of the Number of Crested Cushions in Runzhou White-Crested Ducks on Serum Biochemical Parameters

SIMPLE SUMMARY: The Runzhou white-crested (RWC) duck is a unique breed with excellent ornamental and economic value. It has complex feather protrusions, collectively known as crest cushions, which mainly comprise prominent soft tissues covered by skin and feathers. In this study, the number of crest cushions and various serum biochemical parameters of RWC ducks were observed and measured. The results showed that the number of crest cushions could be used to directly reflect the size of the crest. As the number of crest cushions increased, the weight and mortality increased. In addition, the number of crest cushions had a positive effect on various serum parameters, such as various mineral elements as well as triglyceride and immunoglobulin levels. Therefore, it is preliminarily speculated that the number of crest cushions may indirectly affect the health and immune performance of RWC ducks. ABSTRACT: We investigated the effects of crest cushions in Runzhou white-crested (RWC) ducks. A total of 322 duck eggs were collected for incubation; 286 eggs were fertilized, and 235 RCW ducks were hatched. All the RWC ducks were weighed after 100 days and counted, and the volume of the crest cushion was measured. The number of crest cushions was positively correlated with the body weight, volume of the crest cushion, and distance from the mouth (p < 0.05). The serum Ca, Mg, Fe, Cu, Zn, and Se contents in the multiple-crest-cushion group were significantly higher (p < 0.05), as were the levels of triglycerides, immunoglobulin A, immunoglobulin G, immunoglobulin M, and immunoglobulin D (p < 0.01). The opposite results were seen for glycosylated low-density lipoprotein (p < 0.01). Propionic acid and acetic acid contents differed significantly between the two groups (p < 0.05), as did butyric acid content (p < 0.01), being higher in the multiple-crest-cushion group. Thus, an increase in the number of crest cushions coincided with a change in various serum biochemical indicators. The number of crest cushions might be involved in regulating various mechanisms of RWC ducks and might have an immunoregulatory effect.