Substitution effect of protein source with tea waste on productive performances and ruminal fermentation in crossbred Saanen lactating goats

Abstract

Tea waste (TW) has a protein content of approximately 30% and the potential to replace other protein sources. However, the effect of dietary TW supplement is still ambiguous. The objective of this study was to investigate the effect of three levels of a dietary TW supplement on the performances and physiological changes in goats. Nine multiparous crossbred Saanen lactating goats were arranged in three replicates of a 3 × 3 Latin square. The three groups of goats were fed with 0, 5, or 10 by weight [wt%] dry matter [DM] basis TW, respectively, for a 21-day period. All diets were a total mixed ration (TMR) containing a 40:60 (DM basis) ratio of concentrate: roughage. The goats were weighed at 15 and 21 days. Faeces and urine were collected during the last 7 days of each period. The TW addition had no effect on the DM intake (DMI), DMI% and body weight. The milk protein content in goats on a 10 wt% TW diet was significantly higher (p < 0.05) than that of goats on the other diets. The milk lactose of both TW diets significantly decreased when compared to the control diet (p < 0.01). Goats with 5 and 10 wt% TW tended to decrease digestibility of crude protein (p = 0.10). There were no changes in the DM digestibility, blood glucose, blood urea nitrogen, triglyceride, total protein, ruminal pH, ammonia-nitrogen, total volatile fatty acids, acetic acid (A), propionic acid (P), A:P ratio, nitrogen balance, allantoin excretion and methane emission among treatments. Diets with 5 or 10 wt% TW (DM basis) could be used to replace other plant protein sources.

Highlights

• The tea waste replaced as protein source up to 10% in goat feed with no effect on dry matter intake, blood profile and methane production.

• The 10% tea waste diet increased milk protein content in dairy goat.

• Low dose of condensed tannin in tea waste provided more protein absorption in small intestine by reducing ruminal NH₃–N level.

Keywords:

• Crossbred dairy goat
• methane emission
• tannin
• tea waste
• volatile fatty acids

Acknowledgment

The authors greatly appreciate Prof. Somchai Chanpongsang for his advice and fruitful comments.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from the corresponding author, upon reasonable request.

Additional information

Funding

This work was supported by the 90th Anniversary of Chulalongkorn University Fund (Ratchadaphiseksomphot Endowment Fund) under Grant Number GCUGR1125613091M.