Involvement of Quebracho tannins in diet alters productive and reproductive efficiency of postpartum buffalo cows

1Introduction

Buffalo population plays a prominent role in Egyptian rural livestock production system. In the Mediterranean regions, buffalo cows are widely farmed in North Africa and their farming concentrated around the Nile delta for producing milk and beef (Perera, 2011). In spite of buffalo farming spreading out, the sustainability improvement in milk and meat production is very weak. Indeed, this weakness was basically due to an improvement in farming management tools rather than to genetic selection (Barile, 2005). Reproductive efficiency of buffalo is often compromised by harsh environmental conditions, socio-sexual cues, photoperiod and nutritional status through feed quality and availability (Perera, 2011). Increasing awareness of hazards associated with the use of antibiotic and chemical feed additives (OJEU, 2003), legislators in Europe have moved to prohibit the use of growth-promoting antibiotics in animal feed from the end of 2005 (Marshall and Levy, 2011). The opportunity to exploiting phytogenic substances e.g. tannins have gained attention in livestock nutrition as natural feed additive alternatives for antibiotics (Bodas et al., 2012) to enhance livestock productivity (Makkar et al., 2009, Sallam et al., 2017). Natural plant compounds, such as condensed tannin (CT) improve nitrogen (N) utilization due to an effective rumen escape of dietary protein (Min et al., 2005) and enhance lactation performance and ovulation rate (Min et al., 2003). Additionally, these compounds may prevent reproductive problems in cows that are associated with high level of plasma urea N concentration (Ferguson, 1996). Tannins in high concentrations can be detrimental to reproductive aspects (e.g. ovulation rate, embryo loss and conception rate [CR]) (Min et al., 2001) and to milk production (Gilboa et al., 2000). In the light of shortage of feedstuffs in developing countries, and thus the insufficient nutrient requirements for milk and beef production to meet the over growing human demands, one of the possible avenues to overcome this problem is to look for the efficiency of using tanniniferous plants to compensate for such a deficiency. Information on the supplementation of CT extracts in diets of buffalo to assess nutrient utilization, lactational performance and reproductive efficiency is lacking. Thus, our hypothesis was directed to investigate whether Quebracho tannins (QT) supplementation to the diet of milking buffalo cows would have consistent response on productive and reproductive performances.

2Materials and methods

2.5Ultrasound examination

Ovarian activities and pregnancy diagnoses were examined by using ultrasonography. A real time B-mode scanner (FALCO, USA) equipped with multi frequency (5 and 7.5 MHz) linear array probe was used. Buffalo cows were deprived from feed for 12 h before examination. The probe was pushed gently through the rectum until the anechoic content of the bladder become visible on the monitor then the probe was rotated 90° clockwise and 180° counterclockwise across the reproductive tract until both ovaries and uterine horns were scanned. Diameters and locations of the follicles and corpora lutea on the ovaries were mapped and recorded. Pregnancy diagnosis was carried out on d 35 post insemination. Detection of an anechoic uterus, allantois fluids and/or embryo was considered positive signs of pregnancy. Fig. 1 presents an outline of the time schedule on the experimental buffalo cows.

Fig. 1

Time schedule of ovulation synchronization, artificial insemination and pregnancy diagnosis. UD = ultrasound diagnosis; GnRH: gonadotropin-releasing hormone; PGF2α = prostaglandin F 2α; TAI = timed artificial insemination; QT = Quebracho tannins.

Fig. 1

3Results and discussion

Impacts of various level of QT supplementation to buffalo cows at early lactation on milk yield, FCM and milk composition are shown in Table 2. Supplementation of QT₁₀₀ had no significant effect on milk yield but QT₂₀₀ decreased (P < 0.05) it compared with the control. Also, supplementation of both QT₁₀₀ and QT₂₀₀ decreased (P < 0.05) FCM compared with control. The accumulated effect of QT treatment by time produced a consistent overlapping trend in control and QT₁₀₀. However, QT₂₀₀ treatment resulted in a mild fluctuating decrease in milk yield between wk 2 and 10 of the experiment. Supplementation of QT had no significant effect on milk fat and protein percentages, although their yields decreased (P < 0.05) significantly when QT₂₀₀ was provided. The SNF percentage and yield decreased (P < 0.05) by supplementing QT₁₀₀ compared with the control group. Moreover, SNF yield decreased (P < 0.05) with either dose of QT. The yield of lactose declined (P < 0.05) with supplementing QT₂₀₀. Overall time had significant effect on SNF yield, lactose percentage and yield, and milk density. Moreover, there was significant QT × time interaction on milk yield, milk fat percentage, SNF percentage and yield, lactose percentage and yield, and milk density.

Tannins extract has been suggested as a potentially practical feed additive for protecting dietary protein against rumen microbial degradation. Inclusion of tannins extract in ruminant diet exerts many favorable impacts on ruminant livestock nutrition considering their types, concentrations, chemical structures and physiological status of the consuming species (Hagerman and Butler, 1991). Consuming quantities of tannins showed a magnitude of dosage-dependent effect. Moreover, the effects of CT are not similar as they depend upon their reactivity which is related to their chemical structure (Bueno et al., 2008). Tannins supplementation to ruminant diets depresses feed intake as a result of reduced palatability and decreased rate of digestion (Mueller-Harvey, 2006). Negative effects on milk yield, milk fat and protein values due to the addition of QT to the buffalo diets are consistent with the current results, Wang et al. (1996) observed that inclusion of Lotus corniculatus in lactating ewe's diets increased milk yield, milk protein and lactose percentages. These effects might be related to the increased metabolizable protein supply from the protein-binding action of CT (Patra and Saxena, 2011). The current finding of the reduction in milk yield is in agreement with the finding by Maamouri et al. (2011). Several studies have demonstrated that protein protection resulted in an increase of milk yield for cows (Woodward et al., 1999), dairy goats (Rouissi et al., 2006) and sheep (Penning et al., 1988). These findings apparently are inconsistent with the findings of Waghorn et al. (1999) who reported better animal performance with dietary inclusion of CT up to 100 g/kg DM. Moreover, these results in the present study disagree with those of Wang et al. (1996) in dairy sheep and Woodward et al. (1999) in lactating cows who found that milk protein increased with dietary CT supplementation. Inclusion of CT in the diet of dairy ewes had no effect on DM intake, but a tendency of milk yield to decline with lower milk fat percentage was observed (Molle et al., 2009). These might be related to the type and dose of CT. On the other hand, lower doses of CT varying from 4.5 to 44.5 g/kg DM (Wang et al., 1996, Benchaar et al., 2008) were safely used. These results of high-forage diets provided to buffalo cows are inconsistent with Dschaak et al. (2011) where QT supplementation to dairy cows did not influence milk yield which averaged 34.6 and 36.1 kg/d for the high-forage and low-forage diets, respectively. In addition, formation of QT-protein complex resulted in lower rumen protein degradation and ammonia N (NH₃-N) production, consequently decreased milk urea, but efficiency of N use for milk N was not affected.

Effects of QT supplementation on lactating buffalo cows at an early lactation on follicular dynamics are shown in Table 3. Supplementation of QT₁₀₀ and QT₂₀₀ tended to decrease total number of follicles, number of small follicles and progesterone concentration, but QT₂₀₀ supplementation tended to increase number and diameter of large follicles, and number and diameter of corpus luteum.

Days open, NSPC and CR of lactating buffaloes at early lactation are given in Table 4. The inclusion of QT₂₀₀ shortened DO and decreased NSPC. The inclusion of QT₁₀₀ and QT₂₀₀ reduced CR compared to the control group. Recently, Attia et al. (2016) found negative effects on some reproductive traits due to tannin supplementation in dairy cow diets. There are few studies on the impact of tannins-rich plants or extracts on the reproductive performance of large ruminants, although there are several experiments conducted on the small ruminants. However, short periods of improved nutrient supply before and during mating and reproduction have been known to affect ovulation rate along with increased follicles size and/or number (Bellows et al., 1963), reduced related follicular atresia (Downing and Scaramuzzi, 1991), altered plasma gonadotrophin concentration (Smith, 1988) and increased ovarian sensitivity to gonadotropins (Downing and Scaramuzzi, 1991). These effects probably occur as a result of changes in live weight and body condition, energy and protein intake and absorption from the small intestine (Smith, 1991, Min et al., 1999, Min et al., 2001), plasma concentration of EAA principally branched chain amino acids (BCAA) (Waghorn, 1986, Waghorn et al., 1990, Downing et al., 1995), and levels of plasma metabolic hormones especially insulin (Downing et al., 1995). A large part of the dietary protein is hydrolyzed in the rumen to ammonia, some of which is re-incorporated into microbial protein. Excess ammonia is absorbed from the rumen and metabolized to urea in the liver, leading to increased plasma ammonia and urea concentrations (Min et al., 2001) which may increase the number of early embryonic losses (El-Zarkouny et al., 2007). In other studies, increased dietary rumen degradable N (RDN) intake has similarly increased plasma urea concentration, leading to increased concentration of ammonia and urea in plasma in the utero-oviductal microenvironment (McEvoy et al., 1997) and uterine secretions (Jordan et al., 1983), decreased uterine pH (Elrod and Buttler, 1993), impaired the viability of sperm (Umezaki and Fordney-Settlage, 1975) and oocyte (O'Callaghan and Boland, 1999), decreased fertilization rate and reduced embryo survival and embryonic development in cows (Blanchard et al., 1990) and ewes (Fahey et al., 2001). Thus, subsequent grazing experiments with sheep showed that CT in L. corniculatus increased both ovulation rate and lambing percentage (by 20% to 27%) (Min et al., 1999). These effects of CT were attributed to the reduction in rumen protein degradation to ammonia, increased EAA absorption and reduced early embryonic losses (Min et al., 2001). In New Zealand, an alternative pasture species, L. corniculatus has been investigated (Min et al., 2001, Ramirez-Restrepo et al., 2005). The study compared ewes grazing L. corniculatus with ewes grazing perennial ryegrass/white clover pasture. It was found that the provision of L. corniculatus resulted in a 5% to 33% increase in ovulation rate (maximized if L. corniculatus was fed for 2 to 3 estrus cycles before mating), a 6% to 39% increase in lambing percentage, and a 14% to 26% increase in weaning percentage. The effect of Lotus on ovulation rate was at least partly dependent on the concentration of active tannins. Other effects might include reductions in the concentrations of rumen and plasma ammonia and plasma urea (Min et al., 2001) or changes in the environment of the oviduct and uterus that are conducive to conception, implantation and fetal development (Ramirez-Restrepo and Barry, 2005). Ultimately, it is of crucial importance to minimize the concentration of tannins to improve the reproductive traits. Therefore, supplementing tannins in high concentrations can be detrimental to reproduction (Min et al., 2001).

Table 5 exhibits data of blood metabolites as a consequence to the supplementation of QT. Quebracho tannins had no significant effect on serum total protein, albumin and globulin concentrations. Time had neither affected total protein nor albumin concentration, but influenced globulin concentration (P < 0.05). Supplementation of QT₁₀₀ caused an increase (P < 0.05) in the concentration of serum urea compared with the control and QT₂₀₀. There was a significant (P < 0.05) time effect on serum urea concentration. Supplementation of QT₁₀₀ significantly decreased (P < 0.05) serum creatinine concentration compared with the control. There was no significant effect on serum creatinine concentration by the time during the experimental period. The inclusion of QT had no significant effects on serum glucose, triglycerides and cholesterol concentrations compared with the control. Likewise, there was no significant effect on serum cholesterol concentration due to time period except on d 10 postpartum which revealed significant decrease (P < 0.05).

Quebracho tannins effects on blood metabolites in buffalo cows is consistent with the results reported by Blood et al. (1983) who observed that all blood metabolites were within normal ranges in healthy ruminants with no adverse effects on animal performance or health. Supplementation with plant secondary compounds (PSC) can cause some alterations especially in serum insulin (Devant et al., 2007) and plasma glucose decrease (Joy et al., 2001) or increase (Mohammed et al., 2004), hemolysis and anemia (Bernhoft, 2010), and acting as anticoagulants (Dahanukar et al., 2000). An increase in serum urea was reported, however, serum total protein, albumin and creatinine concentrations were not significantly affected when sheep were fed on diets containing CT (Mahgoub et al., 2008). Accordingly, these various responses might result in negative effects on physiological condition as well as physical and chemical consequences. Bioactive components in PSC have been reported to enhance animals immune responses, as an anti-inflammatory agents (Neto et al., 2005), improved humeral and cellular immunity, modulate immune pathways and immune molecules (Rao and Mishra, 1997, More and Pai, 2011). Inclusion of 15% PBP (tannins, 5.5% DM in diet) in early lactating cow's diet had no significant effects on serum glucose, urea and cholesterol (Rezaeenia et al., 2012). Similarly, Bohluli et al. (2009) reported no changes in serum glucose and urea in early lactating dairy cows. Also, Gholizadeh et al. (2010) found that 10% PBP inclusion in the diet of dairy cows did not change serum cholesterol, urea, triglycerides and glucose. In a study in dairy Saanen goats, it was found that the replacement of 30% PBP as a source of alfalfa hay-tannins resulted in unchanged blood metabolites (i.e., cholesterol, triglyceride, urea, total protein, albumin and glucose). Feeding legumes that contained tannins to sheep and goats showed lower plasma urea N (Woodward, 1988). The significant reduction in plasma urea and ruminal NH₃-N reported by Ben Salem et al. (2005) associated with dietary acacia supply. This might be attributed to the reduced proteolysis and decreased microbial proteolytic activity (Jones et al., 1993).

4Conclusion

Responses to QT as feed additives are dependent upon the type, source and dosage. The culminate outcome of this study indicates little, even none benefits of QT supplementation on productive and reproductive performance of buffalo cows at early lactation. Further studies are required using different proportions of rumen degradable protein and rumen un-degradable protein to confirm these results and to ascertain the mechanisms of QT in ruminant diets.

Conflict of interest

No conflict of interest exists.