Animal performance, rumen microbiota, and fermentation in growing camel calves fed alfalfa hay, Atriplex, or their mixture

Insights into the effect of Atriplex on the performance of growing camels can support Atriplex as an alternative feed resource for sustainable agriculture. This study evaluated the effect of replacing alfalfa hay with Atriplex nummularia hay on rumen microbiota and fermentation, and the growth performance of camel calves. Twenty-four one-year camels were allocated into three groups (n = 8) to feed on one of three forage types for 120 days: concentrate feed mixture (CFM) at 0.9% of body weight (BW) and ad libitum Alfalfa hay (HH); CFM and ad libitum mixture of Atriplex hay and Alfalfa (1:1) (MM); and CFM and ad libitum Atriplex (AA). Bacterial community was dominated by phyla Bacteroidota and Firmicutes. Atriplex inclusion increased the relative abundance of genera Christensenellaceae R-7 group, and Acetitomaculum. while Atriplex declined genera Anaeroplasma and Fibrobacteres as well as rumen methanogens that were dominated by genus Methanobrevibacter. Total volatile fatty acids (VFAs) was similar between camel groups; and camels fed Atriplex had low rumen ammonia and acetic acid, and higher propionic and butyric acids (P < 0.05). Feed intake was similar, and growth rates were 655.00, 540, and 466 g/head/d for groups HH, MM, and AA, respectively, with a significant difference (P < 0.05). Atriplex altered the rumen microbiota and fermentation with a slight negative effect on animal growth. Therefore, Atriplex can replace alfalfa hay partially in the feeding of camel calves in the presence of CFM.