Effects of Cadmium on Rumen Fermentation and Nutrient Digestibility Using Dual Flow Continuous Culture System
Author
Sari, M
Almasi, F
Salari, S
Chaji, M
Keywords
CadmiumDigestibility
Rumen fermentation
Toxicity
Metadata
Show full item recordAbstract
This experiment was conducted to investigate the effects of different doses of cadmium on fermentation characterization and nutrient digestibility using dual flow continuous culture system. Eight dual-flow, continuous culture fermenters were used in 2 replicated periods of 10 d (7 d of adaptation and 3 d of sampling). Fermenters were inoculated with a composited ruminal fluid from 3 beef steers fed a high concentrate diet for at least 2 mo before the beginning of the trial. Anaerobic conditions were maintained by the infusion of N2 at a rate of 40 mL/min. Temperature (38.5°C) and liquid (10%/h) and solid (5%/h) dilution rates were kept constant. Fermenters were fed daily with 120 g dry matter in three equal portions. Treatments arranged as complete randomized block design with control and addition three levels of cadmium (0.1, 1 and 10 mg/l) to the high concentrate diet (15:85 forage to concentrate ratio). Organic matter, dry matter, NDF and ADF digestibility significantly decreased with the addition of 1 and 10 mg/l cadmium to the culture media compered to control treatment (P<0.05). Cadmium significantly decreased total volatile fatty acids concentration, acetate proportion and acetate to propionate ratio. Propionate and butyrate proportion increased significantly in response to cadmium addition (P<0.05). Concentration of NH3-N was significantly decreased in 1 and 10 mg/l cadmium treatments compared with control treatment. The results of this study suggest that cadmium in doses of 1 mg/l or more had strong inhibitory effect on mixed rumen microorganisms.