Effects of Sodium Caseinate and Varying Protein Sources on In Vitro Fermentation of Forages by Mixed Equine Cecal Microorganisms.

The study explored how protein affects fermentation of forages by equine cecal microorganisms. It found that while alfalfa forages were less affected, the right type and amount of protein had significant impacts on the fermentation of grass hay, ultimately enhancing the nutritive value.

Experiment Design and Methodology

• The study used cecal fluid from four cecally cannulated horses, put in fermentation bottles along with a buffer, forage, and protein supplement.
• In the first experiment, sodium caseinate (SC) was used as the protein supplement in varying degrees (from 0-4% crude protein [CP]). The forages used were either alfalfa or warm-season prairie grass hay.
• The bottles were outfitted with monitors for continuous gas pressure, incubated for 48 hours at 39°C, and then tested for a number of fermentation metrics like dry matter disappearance, neutral detergent fiber disappearance, acid detergent fiber disappearance, cumulative gas production, and total volatile fatty acid (VFA).
• In the second experiment, the same method was used but with various protein sources (SC, fishmeal, soybean meal, whey, porcine blood plasma, and L-lysine hydrochloride). These proteins were all tested at 2% additional CP and compared against each other.

Key Findings

• Cultures with alfalfa proved higher in the first set of tests for almost all factors.
• Sodium caseinate raised gas production and lowered pH for cultures with grass hay. Greater amounts of sodium caseinate (1-4% additional CP) increased all test factors, with 4% additional CP also raising total VFA.
• In the second experiment, all protein supplements decreased pH and increased test factors, but the most significant changes were linked to Sodium caseinate, L-lysine, and whey.
• Total VFA and gas production increased for grass hay cultures using all proteins, except porcine blood plasma.

Interpretation and Implications

• From the experiments, the researchers concluded that protein supplementation had more impact on the fermentation of grass hay than alfalfa.
• The source of protein also mattered when it came to influencing the forage’s fermentation.
• The changes observed in fermentation metrics due to protein supplementation enhance the understanding of the digestive process and could potentially be used to improve horses’ nutrition by optimizing their feeds.