Mango (Mangifera indica) seed kernels as untraditional source of energy in Rahmani sheep rations

Abstract

Background

The present work aimed to investigate the impact of partial replacement yellow corn by mango seed kernels (MSK) at different levels of (0, 25, and 50%) on feed and water consumption, water metabolism, nutrient digestibility, nitrogen balance, and rumen fluid parameters.

Methods

Twelve mature male Rahmani sheep of about 58.39 ± 1.22 kg live body weight on average were used to investigate the influence of replacing yellow corn contents (45% in the control ration) by mango seed kernels (MSK) at different levels (0, 25, and 50%) that equal (0, 11.25, and 22.5% of total ration contents) on feed and water intakes, water metabolism, nutrient digestibility coefficients, nitrogen utilization, and some rumen fluid parameters. The animals were randomly assigned to three experimental groups (four animals in each treatment). Sheep fed rations are composed of 50% concentrate feed mixture (CFM) and 50% peanut vein hay (PVH) at portion 3% dry matter (DM) of live body weight (LBW).

Results

The results showed that values of crude protein (CP), crude fiber (CF), and nitrogen-free extract (NFE) of MSK and yellow corn were similar. Meanwhile, MSK has superior ether extract content compared to yellow corn; meanwhile, ash content of yellow corn was lower than ash content of MSK. All tested CFM were isonitrogenous (16.17% CP), but it differs in their contents of gross and digestible energy. On the other hand, all experimental total mixed rations (TMR) were isonitrogenous (14.52% CP) and isocaloric (4177 kcal/kg DM in average). Dietary treatments significantly (P < 0.05) decreased total dry matter intake (DMI) and crude protein intake (CPI) that expressed as (g/h/day, g/kgW^0.75, and kg/100 kg LBW) or gross energy intake (GEI) and digestible energy intake (DEI) that expressed as (Mcal/h/day, kcal/kgW^0.75, and Mcal/100 kg LBW). Inclusion MSK in sheep ration insignificantly (P > 0.05) increased drinking water by 20% and 6.89% for experimental groups fed TMR₂ and TMR₃, respectively, compared to the control one (TMR₁). Incorporation MSK in the rations significantly (P < 0.05) increased insensible losses of water. Dietary treatments significantly (P < 0.05) increased nutrient digestibility coefficients of DM, organic matter (OM), CP, CF, and NFE. Meanwhile, it significantly (P < 0.05) decreased EE digestibility. On the other hand, both values of total digestible nutrient (TDN) and digestible crude protein (DCP) were significantly (P < 0.005) improved. Nitrogen retention (NR) (NR % of nitrogen intake (NI) and NR % of digested nitrogen (DN)) values were significantly (P < 0.05) increased with increasing level of MSK in the sheep ration. Inclusion MSK significantly (P < 0.05) increased ruminal pH; however, it had no significant (P > 0.05) on both ammonia nitrogen (NH₃-N) and total volatile fatty acid (TFVA) concentrations. Sampling time at 3 h post feeding significantly (P < 0.05) decreased ruminal pH in comparison with before and 6 h post feeding; meanwhile, sampling time had no significant effect (P > 0.05) on NH₃-N concentration. Dietary treatment significantly (P < 0.05) increased the interaction between treatments and sampling time for ruminal pH. However, no interaction between treatments and sampling time was observed for both NH₃-N and TVFA concentrations.

Conclusion

The present results revealed that replacement up to 50% of yellow corn by MSK as alternative source of energy could be useful in feeding sheep without any adverse effect on digestion and fermentation processing. Also, it can be used to depress the rations cost.

Background

One of the greatest challenges facing the livestock industry in the developing countries is the provision of nutritionally balanced and cost-effective rations, since feed constitutes about 65–80% of the total cost of intensive livestock production The situation has necessitated the need to source for an alternative or partial replacement of one of the most highly competitive feed ingredients such as maize, which contributes about 60–80% of most formulated diets (Durunna et al. 2000; Abdulrashid et al. 2007; Kayode and Sani 2008).

Maize considered or classified that the major energy source in poultry and animal feeds reach to 50 and 55% of most animal feed formula (Bamgbose et al. 2004). It is equally used in human nutrition, thus creating a stiff competition between human and livestock. The resulting effect is high cost translating into high feed cost.

This has necessitated the search for substitutes such as agro-industrial by-products and other farm residues that can replace maize wholly or partly. Some of agro-industrials by products have been established as partial or total substitute for maize such as Mango seed kernel (Farinu et al. 1999; Shittu et al. 2013).

A lot of untraditional feed resources are yet to be inclusion in the feed bank for low-cost animal production. This is because some of them could be gotten free or at very low costs (Orayaga and Anugwa 2014; Orayaga et al. 2015). Agro-industrial by-products such as mango fruit peels (Roa et al. 2003), mango fruit pulp (Soomro et al. 2013), and mango seed kernel (Oluremi and Musa 2004; Diarra and Usman 2008) and other sources of agro-industrials by-products have been identified as feed resources.

Mango (Mangifera indica) is an important fruit crop grown in the tropics mostly for its pulp. Mango seed, which represents between 20–60% of the fruit, has limited food or industrial use in most producing countries and is therefore wasted. The kernel contained in the seed (mango seed kernel: MSK) is a good source of carbohydrates (58–80%) and contains moderate quantities of proteins (6–13%) and fat (6–16%). The protein of MSK has a good essential amino acid profile, and its oil is a good source of stearic and linoleic acids (Diarra 2014).

Also, mango seed varied from 20 to 60% of the whole fruit, and the kernel as 45 to 75% of the seed (Maisuthisakul and Gordon 2009), this represents between 4 and 18 million tons of mango kernel available per year, due to its abundance and its limited use as a by-product in most parts of the world (Diarra 2014).

The nutrient composition of mango seed kernel on dry matter basis was evaluated by 6.16% crude protein, 13.63% ether extract, 2.23% ash, and 73.35% nitrogen-free extract (Farinu et al. 1999); however, El-Alaily et al. (1996) noted that the gross energy is 4.7 Kcal/g. On the other hand, Farag (2001) noted that the air-dry mango seed kernels contained CP 70 g/kg, EE 128 g/kg, and tannins 67 g/kg. Also, mango seed kernels contain 6% DCP and 70% TDN, and it is rich in tannins which may vary from 5 to 7%. So it can be used as one of the ingredients in livestock rations (Cheeke 1991; Sindhu et al. 2002).

So, this work was carried out to study the impact of partial replacement yellow corn by mango seed kernels at levels of (0, 25, and 50%) on feed and water consumption, water metabolism, nutrient digestibility, nitrogen balance, and rumen fluid parameters.

Methods

The present experiment was carried out at the Sheep and Goats’ Units in El-Bostan area in Nubaria (located on the desert road, 112 km North Cairo city, near from Alexandria) which belongs to the Animal Production Department, National Research Center, Dokki, Giza, Egypt.

Animals and feeds

Twelve mature male Rahmani sheep of about 58.39 ± 1.22 kg live body weight approximately on average were used to establish the impact of replacing yellow corn contents (45% in the control ration) by mango seed kernels at different levels (0, 25, and 50%) that equal (0, 11.25, and 22.5% of total ration contents) on feed and water intakes, water metabolism, nutrient digestibility coefficients, nitrogen utilization, and some rumen fluid parameters. The animals were randomly assigned to three experimental groups (four animals in each treatment).

Sheep fed rations are composed of 50% concentrate feed mixture (CFM) and 50% peanut vein hay at portion 3% DM of live body weight.

Apparent digestibility, nutritive values, and nitrogen balance

Animals were housed in individual metabolic cages. Cages allowed catching feces separately from the urine which was collected in attached glass containers containing 50 ml of 10% sulfuric acid. The digestibility trial consisted of 14 days as a preliminary period followed by 7 days for feces and urine collection.

The animals were fed on 3% of live body weight. Rations were offered in two portions, CFM at 8.00 a.m. followed by main roughage source {peanut vein hay (PVH)} at 9.00 a.m. Water was offered twice daily at 11.00 a.m. and 2.00 p.m. During the collection period, feces and urine were quantitatively collected from each animal once a day at 7.00 a.m. before feeding. Actual quantity of feed intake and water consumption was recorded. A sample of 10% of the collected feces from each animal was sprayed with 10% sulfuric acid and 10% formaldehyde solutions and dried at 60 °C for 24 h. Samples were mixed and stored for chemical analysis. Composite samples of feeds and feces were finely ground prior to analysis. Also 10% of the daily collected urine from each animal was preserved for nitrogen determination. The nutritive values expressed as the total digestible nutrient (TDN) and digestible crude protein (DCP) of the experimental rations were calculated by classical method that described by Abou-Raya (1967).

Chemical analysis (%) of ingredients, concentrate feed mixture (CFM), and experimental total mixed rations (TMR) are presented in Tables 1, 2, and 3. Feeds and water intakes were also recorded during the digestibility trials

Table 1 Chemical analysis of feed ingredients

Table 2 Composition and chemical analysis of concentrate feed mixture

Table 3 Chemical analysis of the experimental total mixed ration

Rumen fluid parameters

Rumen fluid samples were collected from all animals at the end of the digestibility trial before feeding (0 h), 3 h post feeding, and 6 h post feeding via stomach tube and strained through four layers of cheesecloth. Samples were separated into two portions, the first portion was used for immediate determination of ruminal pH and ammonia nitrogen concentration, while the second portion was stored at−20 °C after adding a few drops of toluene and a thin layer of paraffin oil till analyzed for TVFAs.

Analytical procedures

Chemical analysis of ingredients, concentrate feed mixture (CFM), experimental total mixed ration (TMR), and feces samples were analyzed according to AOAC (2005) methods.

Ruminal pH was immediately determined using digital pH meter. Ruminal ammonia nitrogen (NH₃-N) concentrations were determined applying NH₃ diffusion technique using Kjeldahl distillation method according to AOAC (2005). On the other hand, ruminal total volatile fatty acids (TVFAs) concentrations were determined by steam distillation according to Warner (1964).

Gross energy (Kcal/Kg DM) calculated according to Blaxter (1968). Each g CP = 5.65 Kcal, g EE = 9.40 Kcal, and g (CF and NFE) = 4.15 Kcal.

Digestible energy (DE) was calculated according to NRC (1977) by applying the following equation: DE (kcal/kg DM) = GE × 0.76.

Neutral detergent fiber (NDF) was calculated according to Cheeke (1987) using the following equation: NDF% = 28.924 + 0.657 × CF%.

Non-fibrous carbohydrates (NFC) were calculated according to Calsamiglia et al. (1995) using the following equation: NFC = 100 – {CP + EE + Ash + NDF}.

Statistical analysis

Collected data of feed and water intake, water metabolism, nutrient digestibility, and nitrogen balance were subjected to statistical analysis as one way analysis of variance using the general linear model procedure of SPSS (2008). Duncan’s multiple range test (Duncan 1955) was used to separate means when the dietary treatment effect was significant according to the following model:

$$ {\mathrm{Y}}_{\mathrm{i}\mathrm{j}}=\mu +{\mathrm{T}}_{\mathrm{i}}+{\mathrm{e}}_{\mathrm{i}\mathrm{j}} $$

where Y_ij = observation; μ = overall mean; T_i = the effect of mango seed kernels (MSK) levels for i = 1–3, 1 = control ration contained 45% yellow corn (0% MSK), 2 = replaced 25% of yellow corn by MSK, and 3 = replaced 50% of yellow corn by MSK; and e_ij = the experimental error.

Meanwhile, data of rumen fluid parameters was statistically analyzed as two factorial analyses of variance according to the following model:

Y_ijk = μ + T_i + S_j + (TS)_ij + e_ijK

where Y_ijk = observation; μ = the overall mean; T_i = the effect of mango seed kernels (MSK) levels for i = 1–3, 1 = control ration contained 45% yellow corn (0% MSK), 2 = replaced 25% of yellow corn by MSK, and 3 = replaced 50% of yellow corn by MSK; S_j = the effect of sampling time for j = 1–3, 1 = before feeding (0 h), 2 = 3 h post feeding, and 3 = 6 h post feeding; (TS)_ij = the interaction of MSK levels and sampling time; and e_ijK = the experimental error.

Results

Chemical analysis of feed ingredients

Data illustrated in Table 1 cleared that value of crude protein, crude fiber, and nitrogen-free extract of mango seed kernel (MSK) were similar to that of yellow corn. Meanwhile, MSK is superior in their content of ether extract in comparison with yellow corn; the corresponding values of EE were 10.45 and 4.01 for MSK and yellow corn, respectively. On the other hand, ash content of yellow corn was lower than ash content of MSK; the corresponding values of ash were 1.40 and 2.38 for yellow corn and MSK, respectively.

Composition and chemical analysis of concentrate feed mixture

Results of Table 2 showed that MSK replaced 0, 25, and 50% of yellow corn content in basal ration that incorporated at 45% of ration formula. All tested CFM were isonitrogenous (16.17% CP), but it differs in their contents of gross and digestible energy; this relates to different contents of MSK for their content of EE that reach to 10.45% in comparison with that found in yellow corn (4.01%). Also, this may be related to differences in their content of NFE in yellow corn (83.05%) compared to MSK that contained 75.03 % of NFE. On the other hand, NDF content was almost similar in yellow corn and MSK. Meanwhile, non-fibrous carbohydrates (NFC) values were slightly decreased with increasing the level of replacement.

Chemical analysis of the experimental total mixed ration

Data of Table 3 cleared that all experimental total mixed rations (TMR) were isonitrogenous (14.52% CP) and isocaloric (4177 kcal/kg DM in average). Other different nutrients were almost nearly in their values among different TMR for (OM, CF, ash, and NDF. But it slightly differs in their contents of EE, NFE, and NFC.

Feed intake by the experimental groups

Results obtained in Table 4 should be changed to dietary treatments that significantly (P < 0.05) decreased CFM and PVH intake; total DMI and CPI that were expressed as g/h/day, g/kgW^0.75, and kg/100 kg LBW; or GEI and DEI that were expressed as Mcal/h/day, kcal/kgW^0.75, and Mcal/100 kg LBW. Also in significant (P > 0.05), decrease was noticed for both TDNI and DCPI that were expressed as g/kgW^0.75 and kg/100 kg LBW. Meanwhile, replacement yellow corn by MSK at 25 or 50% significantly (P < 0.05) increased both TDNI and DCPI that were expressed as g/h/day.

Table 4 Feed intake by the experimental groups

Water consumption and metabolism by the experimental groups

Dietary treatments had no significant effect on drinking water, feed water, and total water intake that were expressed as ml/h/day; ml/kgW^0.75; L/100 kg LBW; and L/kg DM intake (as presented in Table 5). However, the present results mentioned that inclusion MSK in sheep ration insignificantly (P > 0.05) increased drinking water by 20% and 6.89% for experimental groups fed TMR₂ and TMR₃, respectively, compared to the control one that received TMR₁. On the other hand, water metabolism data showed that incorporation MSK in the rations significantly (P < 0.05) increased insensible losses of water, and the corresponding values were 1109, 2604, and 2673 m/h/day for the three experimental group sheep fed TMR₁, TMR₂, and TMR₃, respectively (Table 5).

Table 5 Water consumption and metabolism by the experimental groups

Nutrient digestibilities and nutritive values of the experimental groups

Data presented in Table 6 cleared that replacement 25 or 50% of yellow corn content in the control ration by MSK significantly (P < 0.05) increased nutrient digestibility coefficients of DM, OM, CP, CF, and NFE. Meanwhile, it significantly (P < 0.05) decreased EE digestibility. On the other hand, both values of TDN and DCP were significantly (P < 0.005) improved when MSK replaced at 25 or 50% of yellow corn content in the control ration.

Table 6 Nutrient digestibilities and nutritive values of the experimental groups

Nitrogen utilization by the experimental groups

Data of Table 7 showed that dietary treatments had no significant effect (P > 0.05) on nitrogen intake (NI), fecal nitrogen, and digested nitrogen (DN). On the other hand, urinary nitrogen was decreased with increasing level of substituting of yellow corn by MSK. The present results mentioned that nitrogen retention (NR) (NR % of NI and NR % of DN) values were significantly (P < 0.05) increased with increasing level of MSK in the sheep ration.

Table 7 Nitrogen utilization by the experimental groups

Rumen fluid parameters of the experimental groups

Data of ruminal parameters are presented in Tables 8, 9, and 10. Replaced 25 or 50% of yellow corn content in the control ration by MSK significantly (P < 0.05) increased ruminal pH; however, it had no significant (P > 0.05) on both ammonia (NH₃-N) and total volatile fatty acid (TFVA) concentrations. On the other hand, sampling time at 3 h post feeding significantly (P < 0.05) decreased ruminal pH in comparison with before and 6 h post feeding; meanwhile, sampling time had no significant effect (P > 0.05) on NH₃-N concentration.

Table 8 Main effects of treatments or sampling time on rumen fluid parameters of the experimental groups

Table 9 Effect of interactions between treatments and sampling time (TxS) on rumen fluid parameters of the experimental groups

Table 10 Results of ANOVA for rumen fluid parameters of the experimental groups

The present results also showed that incorporation MSK as alternative source of energy for yellow corn significantly (P < 0.05) increased TVFA concentration compared to the control that contained yellow corn with 0% MSK (Table 8).

As described in Tables 9 and 10, dietary treatment significantly (P < 0.05) increased the interaction between treatments and sampling time for ruminal pH. However, no interaction between treatments and sampling time was observed for both NH₃-N and TVFA concentrations.

Discussion

The present results showed that MSK could be considered a good quality ingredient like yellow corn and could be used in animal ration formulation. Also, these results are in agreement with those noted by Diarra (2014) who reported that mango seed kernel (MSK) is a good source of carbohydrates (58–80%) and contains moderate quantities of proteins (6–13%) and fat (6–16%). Meanwhile, Anigbogu et al. (2006) showed that proximate analysis of Mangifera indica kernel content 3.0, 8.13, 73.1, 9.0, and 5.2% for CF, CP, NFE, EE, and ash, respectively. Also, Okoruwa et al. (2015) found that chemical composition of MSK was 5.90% CP, 0.89% CF, 5.46% EE, 2.25% ash, and 76.06% NFE. On the other hand, Farag (2001) found that air-dried mango seed kernels contained 70 g/kg of CP and 128 g/kg of EE. In addition to those literatures on proximate composition of MSK, discuss the implications of the contents. Also, Cheeke (1991) and Sindhu et al. (2002) recorded that mango seed kernels contain 6% DCP and 70% TDN, and it is rich in tannins which may vary from 5 to 7%, and it can be used as one of the ingredients in livestock rations. Meanwhile, Odunsi and Farinu (1997) reported that mango seed kernel (MSK) contains 5.59% crude protein, 2.13% ether extract, 2.34% ash, 5.32% crude fiber, and 78.62% nitrogen-free extracts and metabolizable energy was determined by 3.17 kcal/g. However, Odunsi (2005) noted that seed kernel contained 61.6 g crude protein, 136.2 g ether extract, 22.3 g ash, 46.4 g crude fiber, 673.5 g nitrogen-free extract/kg. Also, Elegbede et al. (1996) recorded that mango seed kernel had 6.0% protein, 12.8% fat, 32.8% carbohydrate, 2.0% crude fiber, and 2.0% ash. Meanwhile, Dhingra and Kapoor (1985) observed that mango seed kernels constituted about 18% of the total fruit and contained 5% protein and 6–7% crude fat.

Data of Tables 2 and 3 showed that all tested experimental concentrate feed mixture (CFM) and total mixed rations (TMR) were formulated to cover requirements of sheep according to NRC (1985).

Feed intake by the experimental groups were in harmony with those noticed by Anigbogu et al. (2006) who noted that replacement maize with ground Mangifera indica kernel significantly (P > 0.05) decreased total DMI (g/d/day) and DMI (g/W^0.75kg). Also, the present results in agreement with those noted by Odunsi and Farinu (1997) who reported that increasing substitution of maize above 30% reduced (P < 0.05) feed intake relative to the control of finishing broilers during period (28–63 days). Also, Joseph and Abolaji (1997) recorded that there was no significant difference (P > 0.05) in average daily feed intake of chicks that fed diets containing 0% (control), 10% raw, and 15%, 20%, and 25% cooked mango kernels quantitatively substituted for maize. On the other hand, Patel et al. (2004) showed that inclusion of mango seed kernel at 25% of sheep ration significantly increased DMI that was expressed as g/kg W^0.75, but it insignificantly increased DMI that was expressed as Kg/100 kg. Meanwhile, Saiyed et al. (2003) recorded that receiving weaner kids’ diet containing 25% MSK had no significant effect on dry mater intake that was expressed as g/h/day; kg/100 kg live body weight; and g/kgW^0.75 CP, DCP, and TDN intake.

Data of water consumption and metabolism by the experimental groups that were presented in Table 5 were in harmony with those found by Patel et al. (2004) who reported that incorporation of mango seed kernel at 25% of sheep ration formula significantly increased water intake that was expressed as L/100 kg live body weight, but, in contrast, it insignificantly decreased water intake that was expressed as L/kg DMI. Meanwhile, Saiyed et al. (2003) found that feeding weaner kids’ ration containing 25% MSK significantly increased water intake that was expressed as L/h/day, L/kg DMI, L/100 kg live body weight, and ml/kgW^0.75. Also, anonymous (1993) noted that non-significant average daily water intake per 100 kg body weight by marwari, patanwadi, and merino x patanwadi lambs fattened on either conventional or non-conventional concentrate mixture.

Results of nutrient digestibilities and nutritive values of the experimental groups that presented in Table 6 are not in agreement with those noted by Patel et al. (2004) who showed that inclusion of 25% MSK in weaner lambs ration had no significant effect on nutrient digestibility coefficient of DM, OM, CP, CF, EE, and NFE. Also, they observed that both TDN and DCP were not significantly affected by the incorporation of 25% MSK in the ration compared to the control ration that contained 38% corn with 0% MSK. Meanwhile, Anigbogu et al. (2006) noted that feeding sheep rations substituted maize offal at 0, 25, 50, 75, and 100% by Mango (Mangifera indica) seed kernel had no significant (P > 0.05) on nutrient digestibility coefficients of DM, OM, and CF; however, CP digestibility significantly decreased; but EE and NFE digestibility coefficients were significantly (P < 0.05) increased compared to the control one that contained 60% maize offal. On the other hand, Saiyed et al. (2003) observed that inclusion of 25% MSK in weaner kids’ ration had no significant effect on all nutrient digestibility coefficients (DM, OM, CP, CF, EE, and NFE) and nutritive values (TDN and DCP).

Nitrogen utilization by the experimental groups (Table 7) were in agreement with those noted by Saiyed et al. (2003) who recorded that weaner lambs that received 25% MSK ration contained in significant improved their nitrogen balance in comparison with the control one. On the other hand, Okoruwa et al. (2013) noted that those values of nitrogen (N) intake (g/day); fecal N output (g/day); urinary N output (g/day); N-balance (g/day); N-balance BW^0.75; N-retention (g/day); and N-retention (%) were significantly (P < 0.05) increased with inclusion mango peels at 32% in West African Dwarf goats ration. In contrast, Anigbogu et al. (2006) noticed that replacing maize offal at 25, 50, 75, and 100% by mango (Mangifera indica) seed kernel significantly (P < 0.05) decreased nitrogen retention compared to the control one.

The results of rumen fluid parameters of the experimental groups that presented in Tables 8, 9, and 10 were in agreement with those obtained by Omer and Abdel-Magid Soha (2015) who reported that ruminal pH value and ammonia nitrogen concentration significantly (P < 0.05) decreased at 3 h post feeding, while total volatile fatty acid concentration significantly (P < 0.05) increased at the same time in comparison with the control when Ossimi lambs fed on rations containing different levels (0, 5, 10, and 15%) of dried tomato pomace as agro-industrials by-product used in sheep ration formulation.

Ruminal pH is one of the most important factors affecting the fermentation and influences its functions. It varies in a regular manner depending on the nature of the diet, and on the time, it is measured after feeding and reflects changes of organic acids quantities in the ingesta. The level of NH₃-N and TVFAs as end products of fermentation and breakdown of dietary protein has been used as parameters of ruminal activity by Abou-Akkada and Osman (1967).

The results of ruminal fermentations showed that increasing TVFAs might be related to the more utilization of dietary energy and positive fermentation in the rumen.

The reduction of ammonia nitrogen in the rumen liquor appears to be the result of increased incorporation of ammonia nitrogen into microbial protein, and it was considered as a direct result to stimulated microbial activity, while increasing TVFAs might be related to the more utilization of dietary energy and positive fermentation in the rumen. The addition of more fermentable carbohydrate to ruminant rations causes a decrease in rumen ammonia (Tagari et al. 1964) probably due to a greater uptake of ammonia by rumen microorganisms in support of enhanced microbial growth. The rate of TVFA’s production may in this situation exceed the rate of TVFA’s absorption through the rumen epithelium, and TVFA’s concentration in the rumen juice is increased (Van'tKlooster 1986).

It should be mentioned that TVFA’s concentration in the rumen is governed by several factors such as dry matter digestibility, rate of absorption, rumen pH, transportation of the digesta from the rumen to the other parts of the digestive tract and the microbial population in the rumen and their activities (Allam et al. 1984). Increasing of ruminal TVFA’s concentration is an indicator for better utilization of dietary carbohydrate as described by Fadel et al. (1987).

Conclusion

It can be concluded that mango seed kernel can be used to replace up to 50% of yellow corn content in the sheep rations without any adverse effect on their feed and water intake, water metabolism, digestion coefficients, nitrogen balance, and ruminal fermentation. Consequently mango seed kernel which is not competing and non-conventional feed stuff for animals was found useful as an economic replacement for energy materials like yellow corn