Diet is the most direct way to affect the rumen microbial community. The objective of this study was to examine the effects of different diets on ruminal methanogen composition in cashmere goats. Twenty-four cashmere goats were randomly divided into four groups that were fed alfalfa hay (AH), alfalfa hay plus concentrate (AHC), corn stalks (CS), and corn stalks plus concentrate (CSC). The concentration of ammonia-N for the group fed AHC was substantially higher than in the other groups. The concentrations of total VFAs, acetate, and propionate in AH and AHC groups were higher than in the CS and CSC groups. The abundance of archaea was markedly different among different groups based on a high-throughput sequencing method. The abundance of Cand;'datus_Methanomethylophilus was 21.28% in the AH group, which was higher than the other groups. (Unclassified_c_ Thermoplasmata was the dominant methanogen in the AH and AHC groups, with abundances of 48.09% and 44.97%, respectively; Methanobrevibacter was the dominant methanogen in the CS and CSC groups, with abundances of 41.22% and 20.73%, respectively. A positive correlation was identified between pH and Methanosphaera; a negative relationship was observed between acetate and (Unclassified_o_Thermoplasmatales. In conclusion, the methanogen communities in cashmere goats varied on different diets. In the alfalfa hay-based diets, the Methanomassiliicoccales-affiliated groups were the dominant methanogens in the rumen of the goats. However, when fed the corn stalk-based diets, Methanobrev;bacter was the dominant methanogen in the rumen fluid. The results were related to dietary composition, especially crude protein content.

RESUMO Como elemento traço essencial para os animais, o cobre contribui significativamente para o crescimento e saúde dos animais. Comparado aos oligoelementos inorgânicos, os oligoelementos orgânicos são melhores suplementos; notavelmente, eles são adquiridos através de transformação microbiana. Portanto, nós selecionamos microorganismos enriquecidos com cobre de solos com alto teor de cobre para obter cobre orgânico. O carbamato de sódio diethyldithio trihidratado foi aplicado como agente cromogênico para a determinação de micro quantidades de cobre intracelular através da espectrofotometria. No total, 50 fungos foram isolados após a aplicação bem sucedida da plataforma de triagem para micróbios ricos em cobre. Após análises morfológicas e de biologia molecular, a cepa N-2, identificada como Aspergillus niger sp. demonstrou um melhor potencial de enriquecimento de cobre do que outras. Notavelmente, a tolerância da estirpe ao cobre foi quase três vezes maior que a da Saccharomyces cerevisiae, até 1600mg/L. O conteúdo de cobre ligado orgânico era de 22,84mg Cu/g de célula seca. Usando o método de superfície de resposta Central Composite Design (CCD), nós otimizamos a condição de fermentação (quantidade de inoculação, 13%; temperatura, 28C; pH, 5,0). Em comparação com os resultados da deformação original sob a condição de fermentação de fator único, relatamos um aumento de 24,18% sob as condições otimizadas. Coletivamente, estas descobertas fornecem uma referência para descobrir novos aditivos de cobre orgânico de baixo custo.

ABSTRACT As an essential trace element for animals, copper significantly contributes to the growth and health of animals. Compared to inorganic trace elements, organic trace elements are better supplements; notably, they are acquired through microbial transformation. Therefore, we screened for copper-enriched microorganisms from high copper content soil to obtain organic copper. Sodium diethyldithio carbamate trihydrate was applied as a chromogenic agent for determining micro amounts of intracellular copper through spectrophotometry. In total, 50 fungi were isolated after the successful application of the screening platform for copper-rich microbes. Following morphological and molecular biology analyses, the N-2 strain, identified as Aspergillus niger sp. demonstrated showed better copper enrichment potential than others. Notably, the strain tolerance to copper was nearly thrice that of Saccharomyces cerevisiae, up to 1600mg/L. The content of the organic bound copper was 22.84mg Cu/g dry cell. Using the Central Composite Design (CCD) response surface method, we optimized the fermentation condition (inoculation amount, 13%; temperature, 28(C; pH, 5.0). Compared to the original strain results under the single factor fermentation condition, we reported an increase by 24.18% under the optimized conditions. Collectively, these findings provide a reference for uncovering new and low-cost organic copper additives.