Dietary Supplementation with Putrescine Improves Growth Performance and Meat Quality of Wenchang Chickens

**Background:** Chicken meat is an important source of protein and health-promoting substances like essential amino acids and n-3 polyunsaturated fatty acids. However, intensive rearing conditions can decrease meat quality. Putrescine, a polyamine, plays vital roles in cell proliferation, protein synthesis, and alleviating oxidative stress, suggesting it may improve meat quality. However, high concentrations are toxic. This study hypothesized that an appropriate dietary level of putrescine could improve broiler growth performance and meat quality.

**Methods:** A total of 480 eighty-day-old female Wenchang chickens were randomly assigned to four groups (8 replicates/group, 15 birds/replicate): a control group fed a basal diet, and three experimental groups fed the basal diet supplemented with 0.01%, 0.03%, or 0.05% putrescine for 40 days. Growth performance (initial weight, final weight, average daily gain, average daily feed intake, feed-to-gain ratio) was recorded. At the end of the experiment, 8 chickens per group were selected for blood and breast muscle collection. Measurements included: serum and muscle polyamine levels (putrescine, spermidine, spermine) via HPLC; meat quality traits (pH at 45 min and 24 h, lightness, yellowness, drip loss, shear force); muscle morphology (fiber diameter and cross-sectional area); inosine monophosphate (IMP) content; amino acid profiles; fatty acid profiles; and elemental composition (K, Mg, Na, Zn). Data were analyzed using one-way ANOVA with Duncan's multiple range test in SPSS 26.0, with p < 0.05 considered significant.

**Key Results:** Dietary supplementation with 0.05% putrescine significantly increased final body weight (1990.33 g vs. 1917.98 g in control, p = 0.01) and average daily gain (17.80 g vs. 16.01 g, p = 0.01), and decreased the feed-to-gain ratio (5.49 vs. 6.02, p = 0.02). Serum concentrations of putrescine, spermidine, and spermine were significantly lower in the 0.03% and 0.05% groups compared to control (p < 0.05), but muscle polyamine levels were unaffected. No significant differences were found in carcass traits, meat quality parameters (pH, color, drip loss, shear force), or muscle fiber morphology. The 0.03% and 0.05% putrescine groups had significantly higher contents of methionine, phenylalanine, lysine, aspartic acid, tyrosine, total essential amino acids, and total amino acids in breast muscle (p < 0.05). These groups also had significantly lower levels of multiple saturated fatty acids (including lauric, myristic, pentadecanoic, arachidic, docosanoic, tricosanic, lignoceric acids), erucic acid, cis-11,14,17-eicosatrienoate, linoleic acid, total n-6 polyunsaturated fatty acids, and a lower n-6/n-3 PUFA ratio (18.83 vs. 27.05 in control, p < 0.01). Sodium content was higher in the 0.01% and 0.03% groups (p = 0.01), while IMP, potassium, magnesium, and zinc were not significantly different.

**Clinical Implications:** This study provides evidence that dietary putrescine at 0.05% can enhance growth performance and improve the nutritional quality of chicken meat by increasing essential amino acids and reducing saturated fatty acids and the n-6/n-3 PUFA ratio. These changes may offer cardiovascular health benefits to consumers. The findings support putrescine as a potential feed additive in poultry production, though the study was limited to a 40-day period in female Wenchang chickens, and further research is needed on long-term effects, optimal dosing, and applicability to other breeds and production systems.