This study aimed to investigate the effects of dietary riboflavin levels on the reproductive performance of pigeon breeders and the growth performance and carcass traits of offspring squabs to estimate the riboflavin requirement of pigeon breeders. The natural riboflavin content in the basic diet of corn–peas–soybean–wheat–sorghum–corn gluten is 1.20 mg/kg. Different doses of riboflavin (0, 2.5, 5, 10, and 15 mg/kg) were supplemented with the basal diet to produce five dietary treatments with total riboflavin levels of 1.20, 3.70, 6.20, 10.20, and 16.20 mg/kg. A total of 120 pairs of White King pigeons, aged 60 wks, were randomly allocated into five treatment groups, each consisting of 24 pairs. Each pair was individually raised for 8 wks. After the experiment, an assessment was conducted to evaluate the reproductive performance of the pigeon breeders, as well as the growth and carcass traits of offspring squabs at 28 days of age. The results showed that the dietary riboflavin levels had no significant effect on body weight, feed intake, egg weight, egg production, and egg fertility (p > 0.05). However, pigeons fed a diet without riboflavin had the lowest egg hatchability, egg yolk color, carcass trait, and riboflavin status, while exhibiting higher liver weight and liver index (p < 0.05). Moreover, the indices above showed increased or decreased linearly as the level of riboflavin was increased in the diet. Based on the broken-line regression model, pigeon breeders were determined to require a dietary riboflavin content of 11.4, 13.6, 13.4, 6.60, 4.28, 4.47, 4.67, 6.69, and 6.82 mg/kg to optimize hatchability, eviscerated weight, half-eviscerated weight, breast muscle weight, breast muscle percentage, liver weight, liver index, egg yolk riboflavin, and squab plasma riboflavin, respectively. In conclusion, the optimal supplemental dosage of riboflavin in the diets of pigeon breeders is 13.6 mg/kg.

This study aimed to evaluate the effects of 4-hydroxyphenylacetic acid (4-HPAA), a phenolic acid compound from Yucca schidigera extract, in Caco-2 cells and artificial rearing of pigeons. In vitro experiments showed that 4-HPAA at different levels exhibited higher cell viability than shikimic acid and 3,4-dihydroxybenzoic acid, and with the highest viability observed at 600 μM. Additionally, 600 μM 4-HPAA alleviated LPS-induced upregulation of IL-1β and CASPASE1 expressions (P < 0.05). In vivo results demonstrated that supplemental 4-HPAA at 500, 1000, and 2000 mg/kg levels did not affect the body weight of 25-day-old pigeons (P > 0.05), but all levels increased immunoglobulin G (IgG) and IgM levels (P < 0.05). Compared with control, 2000 mg/kg 4-HPAA significantly reduced serum L-lactic acid, D-lactic acid and lactate dehydrogenase (LDH) activity (P < 0.05); increased spleen and bursa of Fabricius indices and intestinal total antioxidant capacity activity of 25-day-old pigeons (P < 0.05); and elevated ileal barrier-related genes (OCCLUDIN, CLAUDIN1 and MUC2) in 7-day-old pigeons, as well as jejunal MUC2 and ileal OCCLUDIN in 25-day-old meat pigeons (P < 0.05). It also inhibited glycolytic gene hexokinase 2 expression, while upregulating the signaling pathway genes CAMK2G and MKNK1 (P < 0.05). Supplemental 500 and 1000 mg/kg 4-HPAA significantly increased serum total cholesterol levels (P < 0.05). Notably, 500 mg/kg 4-HPAA had an adverse effect on intestinal integrity, as indicated by the highest serum diamine oxidase content, and increased glycolytic gene LDH-B expression; However, it enhanced microbial richness and diversity in the intestines of 7-day-old pigeon (P < 0.05). Besides, 1000 mg/kg 4-HPAA impaired intestinal morphology, as evidenced by a lower ileal villus height-to-crypt depth ratio (P < 0.05), but resulted in the highest abundance of Lactococcus in 25-day-old pigeons. In conclusion, 600 μM 4-HPAA exhibits anti-inflammatory activity in Caco-2 cells, and 2000 mg/kg 4-HPAA promotes immune function and intestinal barrier integrity while inhibiting glycolytic gene expression and the production of related serum metabolites in meat pigeons.

Fatty acid composition of skeletal muscle is an important determinant of meat quality in poultry. In this study, we compared the breast muscle fatty acid profiles of White King (BW, n = 25) and Tarim (TM, n = 23) pigeons using targeted fatty acid quantification under identical feeding and management conditions. Sixteen differential fatty acids were identified, with TM pigeons exhibiting significantly higher levels of palmitic (C16:0), stearic (C18:0), oleic (C18:1n9c), and linoleic (C18:2n6c) acids (p < 0.001). Principal component analysis revealed clear separation between breeds, reflecting distinct fatty acid composition patterns. Kyoto Encyclopedia of Genes and Genomes annotation indicated that differential fatty acids were associated with pathways related to fatty acid biosynthesis, elongation, and degradation. Together, these results describe breed-specific differences in breast muscle fatty acid composition and provide a descriptive biochemical reference for understanding variation in meat quality-related traits among pigeon breeds.

Manganese (Mn) is indispensable for skeletal development in poultry, yet its dietary requirement for meat pigeons has never been established. This study fed 120 pairs of White King pigeon breeders diets containing 28.43, 63.43, 98.43, 133.43, or 168.43 mg/kg total Mn (0, 35, 70, 105, or 140 mg/kg supplemental Mn) for 53 days to assess effects on reproductive performance, squab tibia development, and epiphyseal cartilage gene expression. Egg hatchability responded quadratically (p = 0.006), peaking at 97.9% in the 98.43 mg/kg group and falling to 83.3% at 168.43 mg/kg. Mn concentration in squab crop contents increased linearly with increasing dietary Mn levels provided to breeders (p = 0.009), indicating greater Mn exposure in the sampled offspring. However, this measurement does not directly quantify Mn transfer through pure crop milk. In 28-day-old squabs, serum alkaline phosphatase (ALP) activity was affected by dietary Mn level (overall treatment effect, p = 0.010) and showed a quadratic response (p = 0.003), with the highest activity observed in the 98.43 mg/kg total dietary Mn group. Tibial strength and maximum deflection did not differ among dietary treatments (p > 0.05). Tibial ash percentage showed a significant treatment effect (p = 0.001) and a linear response to dietary Mn level (p = 0.021), although the difference between the basal and highest-Mn groups was relatively modest (49.9% vs. 46.9%). These findings do not provide sufficient evidence of severe impairment of tibial mineralization at the highest dietary Mn level. In tibial epiphyseal cartilage, fibroblast growth factor 23 (FGF23) mRNA expression at 63.43 mg/kg total dietary Mn was approximately 3.85 times that in the basal group, whereas expression at 98.43~168.43 mg/kg did not differ significantly from the basal group. ETS-related gene (ERG) mRNA expression was approximately 5.63~5.85 times that in the basal group at 63.43~133.43 mg/kg, but expression at 168.43 mg/kg was lower than in these intermediate-dose groups and did not differ significantly from the basal group. Quadratic regression analyses based on replicate-level observations revealed significant relationships between dietary total Mn levels and egg hatchability (R² = 0.931, p = 0.0155) and relative ERG expression (R² = 0.783, p = 0.0368). The estimated optimal dietary total Mn levels were 92.63 and 95.34 mg/kg based on egg hatchability and ERG expression, respectively. These findings suggest a preliminary optimal dietary total Mn range of 92.63~95.34 mg/kg for meat pigeons under the conditions of this study, which requires further validation.