Co-ensiling pomegranate (Punica granatum L.) peels and molasses with berseem (Trifolium alexandrinum L.) alters fermentation quality, nutrient composition, ruminal fermentation and methane production in buffalo bulls in-vitro

Abstract

Pomegranate peels are an industrial by-product high in sugar and phytochemical content and pose an environmental concern. Meanwhile, ensiling legume forage such as berseem is difficult due to its lower dry matter content and water-soluble carbohydrate-to-buffering capacity ratio, which leads to a poor fermentation process. To date, no studies have been conducted to investigate the effect of co-ensiling pomegranate peels with berseem. Thus, silage quality was evaluated after co-ensiling of berseem (control) with 50, 100, and 200 g/kg pomegranate peels or 50 g/kg molasses for 0, 15, 30, and 45 days (Experiment 1). Further, rumen nutrient degradation, methane production, and rumen fermentation parameters were evaluated in vitro (Experiment 2). Pomegranate peels (200 g/kg) and molasses reduced silage pH compared to control (4.41 or 3.79 vs. 5.02), ammonia-N (2.66 or 3.14 vs. 13.39 g/kg N), and butyric acid (0.05 or 0.1 vs. 0.96 g/kg DM) however, dry matter (323.5 or 283.6 vs. 212.8) and non-fiber carbohydrates (264.8 or 351.8 vs.136.9 g/kg) were increased, respectively. Pomegranate peels and molasses significantly (P < 0.05) increased rumen nutrient degradation and significantly (P < 0.05) decreased methane and ammonia-N production (Experiment 2). The chemical composition of silage, in-vitro rumen fermentation, and silage quality parameters were significantly (P < 0.05) correlated. Pomegranate peels and molasses have potentially improved silage quality and positively influenced rumen fermentation parameters.

Keywords: Legume forages; Methane production; Pomegranate peels; Rumen fermentation; Silage.

Fig. 1

Ammonia-N (g/kg TN) of berseem ensiled with pomegranate peels and molasses at different levels after 0, 15, 30, and 45 days of ensiling. Con: control; Mls: molasses:50,100 and 200 refer to the inclusion of pomegranate peels at 50,100 and 200 g/kg on a fresh weight basis. Effects of treatment, time, and treatment × time interaction are (P < 0.01). The standard error of the mean (SEM) is 0.55

Fig. 2

Ammonia -N (mg/100 ml rumen buffered liquid) of berseem ensiled with pomegranate peels and molasses at different levels after 30 days of ensiling. Con: control; Mls: molasses; The p-value for the effect treatment (P = 0.6), time (P < 0.01), treatment × time (P < 0.001). The standard error of the mean (SEM) is 1.08

Fig. 3

Pearson correlations between the silage quality parameters and chemical composition of berseem silages throughout the ensiling period. DM: dry matter; OM: organic matter; CP: crude protein; EE: ether extract; NDF: neutral detergent fiber; ADL: acid detergent lignin; NFCM: non-fibrous carbohydrates; FS: Fleig’ score. The number in each square represents the correlation extent; the color represents a significant correlation (p < 0.05), the deeper the color of the square is the more significant the correlation. the red color means a positive correlation, and the green color means a negative correlation

Fig. 4

Pearson correlations between the in vitro fermentation parameters at 24 h of incubation and chemical composition of berseem silages. ADMD: apparent dry matter degradability; TDMD: truly dry matter degradability; TDOM: truly degraded organic matter; NDFD: neutral detergent fiber degradability; MP: microbial protein; TVFA: total volatile fatty acid; A/P: acetate to propionate ratio; CH₄: methane. DM: dry matter; OM: organic matter; CP: crude protein; EE: ether extract; NDF: neutral detergent fiber; ADF: acid detergent fiber; ADL: acid detergent lignin; NFC: non-fibrous carbohydrates. The number in each square represents the correlation extent; the color represents a significant correlation (p < 0.05), the deeper the color of the square the more significant the correlation. the red color means a positive correlation, and the green color means a negative correlation

Fig. 5

Pearson correlation between the invitro fermentation parameters at 48 h of incubation and chemical composition of berseem silages. ADMD: apparent dry matter degradability; TDMD: truly dry matter degradability; TDOM: truly degraded organic matter; NDFD: neutral detergent fiber degradability; MP: microbial protein: TVFA: total volatile fatty acid; A/P: acetate to propionate ratio; CH₄: methane. DM: dry matter; OM: organic matter; CP: crude protein; EE: ether extract; NDF: neutral detergent fiber; ADF: acid detergent fiber; ADL: acid detergent lignin; NFC: non-fibrous carbohydrates. The number in each square represents the correlation extent; the color represents a significant correlation (p < 0.05), the deeper the color of the square the more significant the correlation. The red color means a positive correlation and the green color means a negative correlation