The effect of cooling slope (CS) on the microstructure of hypereutectic Al-22Si-2Fe (% w/w) alloys with 0%, 0.99%, and 1.36% Mn were studied. The results showed that primary Si particles (PSPs), needle-like Fe phases, coarse fishbone-shaped α-Al15(Fe, Mn)3Si2 phases, and eutectic Si could be refined. With such a CS process, the intermetallic compounds in the alloys with different Mn/Fe ratios were examined with an optical microscope, scanning electron microscope, and X-ray diffraction. Moreover, the acicular δ-Al4(Fe, Mn)Si2 and blocky α-Al15(Fe, Mn)3Si2 phases were analyzed by transmission electron microscopy.

We investigated the effects of crossbreeding on slaughter traits and the chemical composition of chicken breast muscle. Trials were conducted using 120 broilers from four lines: Xiao-Shan chicken (XS), Xian-Ju chicken (XJ), Xiao-Shan chicken♂♂ × Xian-Ju chicken♀♀ (Zhenan 1, ZNY1) and Xiao-Shan chicken♂♂ × (Guang-Xi Yellow chicken♂♂×Xian-Ju chicken♀♀) ♀♀ (Zhenan 2, ZNY2). The birds were slaughtered at 120 days of age and the slaughter traits were measured. Breast muscles were sampled to determine chemical composition. The slaughter traits of hybrid chickens were improved. Both hybrid strains had higher intramuscular fat (IMF) and inosine-5'-monophosphate (inosinic acid, IMP). Concentrations of monounsaturated fatty acids (MUFA) in breast muscles from the two hybrids were significantly higher than in the other two breeds (p < 0.05). The concentration of polyunsaturated fatty acids (PUFA) in the breast muscles of the two hybrids was significantly lower than in the other two breeds (p < 0.05). ZNY2 had significantly lower (p < 0.05) concentrations of myristic acid (C14:0). The breast muscle of ZNY1 had significantly higher palmitic acid (C16:0) concentrations than XS, XJ, or ZNY2 (p < 0.05). The concentrations of oleic acid (C18:1) and eicosapentaenoic acid (C20:5n-3, EPA) in breast muscle from the two hybrid lines were significantly higher than the other two breeds (p < 0.05). Breast muscles from XS and XJ chickens contained significantly higher docosahexenoic acid (C22:6n-3, DHA) than the two hybrid lines (p < 0.05). The XS and XJ chickens had lower n-6/n-3 ratios than the two hybrids (p < 0.05). Breast muscles from ZNY1 and ZNY2 contained higher concentrations of essential amino acids (p < 0.05), total amino acids (p < 0.05), and some individual amino acids (p < 0.05). In conclusion, crossbreeding improved the slaughter traits of chickens and increased intramuscular fat and inosinic acid content in breast muscle. The fatty acid and amino acid compositions of breast muscles were also improved by crossbreeding.