Rumen digestion and microbial protein synthesis by growing lambs fed high-concentrate diets: Effects of cereal processing and animal age

Effect of concentrates level on digestibility, ruminal fermentation, and bacterial community in growing camels

Understanding the rumen microbiota of camels under different feeding conditions is necessary to optimize rumen fermentation and productivity. This study aims to investigate the effects of different concentrate supplement levels on digestion, rumen fermentation and bacteria in growing camels. Fifteen growing camels were divided into three groups and were fed alfalfa hay in addition to one of the three concentrate supplement levels based on body weight (BW): low (0.7%), medium (1%), and high (1.3%). Increasing the concentrate supplement level in the diet increased total dry matter intake but had no effect on nutrients digestibility, except for crude protein digestibility, which was enhanced with the high concentrate level. Growing camels at low-level had considerably higher rumen pH than those fed medium or high levels. Increasing the supplement level also increased rumen propionic acid but decreased acetic acid concentration. Principal coordinate analysis showed that concentrate levels clearly separated the ruminal bacterial communities where Bacteroidetes and Firmicutes were the dominant phyla and Prevotella, Ruminococcus, Butyrivibrio, RC9_gut_group, and Fibrobacteres were the dominant bacterial genera. This study expands our knowledge regarding the rumen microbiota of growing camels under different concentrate levels and reveals that medium concentrate levels could be appropriate for growing camels.

Study of morphometric and ruminal parameters in santa inês sheep fed spineless cactus (Opuntia ficus-indica, MILL)

ABSTRACT The present study aimed to morphometrically evaluate the ruminal mucosa and ruminal fluid characteristics of Santa Inês sheep fed different levels of spineless cactus as a replacement for Tifton grass hay. A total of 32 intact male Santa Inês sheep, approximately 180 days old and with a mean weight of 32.0±1.6kg, were studied in a completely randomized design with four treatments and eight replicates. The morphometric measurements evaluated in the ruminal epithelium (papilla height and surface area) were significantly affected (P< 0.05) by supplementation of the diet with spineless cactus, and these effects showed increasing linear trends. Evaluations of the ruminal fluid also showed a significant increasing linear effect (P< 0.05) for ammonia and a quadratic effect for microbial protein. The inclusion of spineless cactus in the sheep diet affects the ruminal epithelium morphology, including the papilla height and surface area, and favors the absorption process in the rumen. The diet containing higher levels of spineless cactus led to maximum microbial protein production. These results characterize spineless cactus as a feasible alternative for feeding sheep during periods of drought, when the typical food source is scarce.

Rumen fermentation and histology in light lambs as affected by forage supply and lactation length

This study determined whether the rumen fermentation and histology traits may reflect the feeding strategy in light lambs (22-24 kg). Thirty-two single Rasa Aragonesa lambs were assigned to one of four treatments in a 2×2 factorial design. The factors were the inclusion of forage in the diet (alfalfa grazing vs. concentrate-fed indoors) and lactation length (weaning at 13 kg vs. suckling until slaughter). A multivariate canonical analysis discriminated individuals among feeding strategies. The main function differentiated weaned concentrate-fed lambs from the rest according to dorsal sac papillae height, ventral sac muscular layer thickness and the proportion of rumen valerate. The second function differentiated suckling concentrate-fed lambs from the rest according to plasma urea levels. Lactation length played an important role on rumen histology and protein utilization, especially in concentrate-fed lambs. Alfalfa grazing light lambs had similar rumen morphometric measures and fermentation characteristics, regardless of milk access.