Abstract: The main objective of the current study is to evaluate tomato pomace silage as a source of roughage feed for lactating animals. Twenty lactating Egyptian buffaloes at the second/third season of lactation were used in the present study. The animals were randomly divided to two groups (ten buffaloes in each) using the complete random design. The animals were introduced to treatments starting on 70 DIM and continued for six weeks. The treatments were, control ration (R1) and it received a Corn Silage (CS) based ration supplemented with Concentrate Fed Mixture (CFM), Clover (C) and Rice Straw (RS) without Tomato Pomace Silage (TPS). The second ration (R2) was similar to the ration in first group with replacing clover by tomato pomace silage. The digestibility coefficients of dry matter, neutral and acid detergent fiber and nutritive values were increased (p<0.05) significantly with tomato pomace silage feeding. The protein and cellulose digestibility coefficients was negatively influenced (p<0.05) by tomato pomace feeding. The feeding of tomato pomace did not alter actual milk yield but it increased (p<0.05) 7% fat-corrected milk yield and milk fat percentage. Other milk composition percentages were not significantly affected. Feeding tomato pomace increased (p<0.05) proportions of polyunsaturated fatty acids, however, milk protein amino acid fraction was negatively affected in most cases. Inclusion of tomato pomace silage in the ration of lactating buffaloes improved feed utilization and economic efficiency compared to control ration. It was concluded that the nutritional value, feed conversion and economic efficiency of rations contained tomato pomace silage improved when used at rate 25% of ration without any adverse effect on performance of lactating buffaloes.
INTRODUCTION
Many of crop residues and agro-industrial by products in most development countries are depended on the highest extent of by-product utilization as an excellent source of nutrients and help to bridge the gap between demand and supply of feedstuffs for livestock. In addition their use can also reduce the cost of feeding, giving higher profits to farmers compared to the costs of the conventional feedstuffs, the safety for animal health and the attractiveness of alternative uses. Agro-industrial by-products divided into two major groups according to the content of moisture and fermentable organic matter (El Shaer, 1999).
Egypt produces up to 8,625,219.00 t of fresh tomatoes annually (FAO., 2012) which most of them are used for processing in tomato cannery factories, producing a considerable amount of wet tomato pomace as a by-product. Tomato pomace which represents 0.05-0.10 of the original weight of tomatoes and it is a mixture of tomato peels, crushed seeds and small amount of pulp that remain after the processing of tomato for juice, paste and/or ketchup (Peralta and Spooner, 2006), has been evaluated to be used in rations for dairy cows (Weiss et al., 1997). On the other hand, it has storage problems because of the high water content about 75% (Elloitt et al., 1981). So, tomato pomace can be fed to ruminant animals for longer periods of time without spoilage, when it is ensiled with or without additives (Mirzaei-Aghsaghali and Maheri-Sis, 2008; Ziaei and Molaei, 2010).
The feeding of ruminants on dried or silage tomato pomace has been studied to dairy cows and sheep (Abdollahzadeh et al., 2010; Fondevila et al., 1994; Weiss et al., 1997). Buffaloes are one of ruminants which their rumen physiological adaptation can utilize inexpensive by-products to meet their maintenance feed requirements, growth, reproduction and production such as meat and milk. No previous researches reported about role of using ensiled tomato pomace on performance of lactating buffaloes especially fatty acids and amino acid profiles in milk.
Therefore, the aim of the present study was to evaluate the effect of ensiled tomato pomace on nutrients digestibility, milk yield and composition, fatty and amino acids profiles in Egyptian Lactating buffaloes.
MATERIALS AND METHODS
Ensiling procedures: Fresh tomato pomace samples were collected from several factories at 6 October, Giza, Egypt. Whole corn plants were chopped to make Corn Silage (CS). The tomato pomace and corn silage were ensiled without any additive and every type of both was preserved manually separated. Silages were kept underground inside the silo with dimensions of (4x3x1.5 m length, width and height). The walls of the silo were covered with polyethylene sheet and the top of the silo was covered by a thin layer of polyethylene sheet (1.0 mm), then a clay layer of approximately 20 cm thickness was spread over the polyethylene sheet for 60 days.
Experimental animals and rations: Twenty lactating Egyptian buffaloes at the second/third season of lactation were used in the present study. The animals were randomly divided into two groups (ten each) using the complete random design. The animals were introduced to treatments starting on 70 DIM and continued for six weeks.
The intended ratio of concentrate to roughage was 40:60% on DM basis. The experimental animals were fed on Corn Silage (CS) based rations. Concentrate Feed Mixture (CFM) was used as the concentrate source. Clover (C) and Rice Straw (RS) were used as source of roughage. The control group (R1) was fed CFM, CS, C and RS, whereas, animals in the second group (R2) was fed on the control ration with replacing C by Tomato Pomace Silage (TPS). Chemical composition of ingredients feeds and experimental rations are presented in Table 1.
Feeding and management: The offered daily feed of both concentrate and roughage were assessed to cover the maintenance as well as the production requirements for each animal from TDN value and Digestible Protein (DP) according to Paul et al. (2002). The rations were recalculated every week based on milk yield and body weight of animals.
Concentrate feed mixture was offered two times daily at 08.00 am and at 06.00 pm, clover or silage were once daily at 11.00 am rice straw was introduced once daily at 2 pm drink water was free every time. Buffaloes were kept under the routine veterinary supervision throughout the whole feeding trial.
| Table 1: | Chemical composition of ingredients feeds and the experimental rations |
| C: Clover, CS: Corn silage, TPS: Tomato pomace silage, CFM: Concentrate feed mixture and RS: Rice straw, 1Cellulose: ADF-ADL, 2Hemicellulose: NDF-ADF, *CFM formulation: 48.50% yellow corn, 25% wheat bran, 10% soybean meal, 13% sunflower meal, 2% limestone, 1.20% salt and 0.30% premix | |
Digestibility trial: A grab sample method was applied at which Acid Insoluble Ash (AIA) was used as an internal marker according to Van Keulen and Young (1977) for determining the nutrients digestibility. Fecal grab samples were collected handily for six successive days at the end of the experiment from each animal. Representative samples were dried in an oven at 60°C for 48 h. The dried fecal samples from each animal were mixed well by equal weights from all collections and saved for chemical analysis.
Dried feed, orts, feces samples were ground through a Wiley mill (Arthur H. Thomas, Philadelphia, PA, USA) using a 1 mm screen. Samples were analyzed for DM (#930.15), N (#954.01), ash (#942.05) and ether extract (EE; #920.39), according to AOAC (2000), while fiber fractionation (i.e., Neutral Detergent Fiber, NDF and Acid Detergent Fiber, ADF) were determined according to Van Soest et al. (1991). Nitrogen free extract was calculated by difference.
Milk sampling and analysis: Buffaloes were milked twice daily and milk weights were recorded. Milk samples from consecutive evening and morning milking were taken and mixed in proportion to yield every week. Milk constituents (for each animal) of total solids, fat, protein, lactose, solids-non-fat and ash were analyzed by Bentley150 infrared milk analyzer (Bentley Instruments, Chaska, MN, USA) calibrated for Egyptian buffaloes milk analysis.
Fatty acids fraction of milk fat was determined using methyl ester boron tri-fluoride method (AOAC., 2000). The fat was extracted and saponified with sodium hydroxide in methanol. The fatty acids were methylated with boron tri-fluoride in methanol, then, extracted with heptane. The fatty acids methyl ester was separated using a gas chromatography with FID detector (PE Auto System XL) with auto sampler and Ezchrom integration system. Carrier gas (He); ca 25 Psi-air 450 mL min-1, Hydrogen 45 mL-split 100 mL min-1 oven temperature 200°C injector and detector 250°C.
Amino acid profile was determined according to Millipore Corporation (1987) using eppendrof-Germany LC3000 amino acid analyzer. The flow rate was 0.2 mL min-1, while pressure of buffer and reagent were from 0.0-50 and 0.0-105 bar, respectively, while reaction temperature was 123°C.
Statistical analysis: Data were analyzed using the general linear model procedure of SAS (2001). One way ANOVA procedure used to analyze the digestibility, blood parameters, feed intake, growth rate data following the next model; Yij = μ + Tij + eij, where: μ is the overall mean of Yij; Tij is the treatment effect; the eij is the experimental error. Significance between the means was determined by multiple range test (Duncan, 1955).
RESULTS AND DISCUSSION
The chemical compositions of feedstuffs and experimental rations are shown in Table 1. The proximate analysis of tomato pomace silage has differences within the different studies. In the present study, the proximate analysis of tomato pomace is compatible with those reported by Maheri-Sis et al. (2012), whereas, there are some differences between chemical composition of tomato pomace silage in current study comparing with the results obtained by others (Abdollahzadeh et al., 2010).
Nutrient digestibility and nutritive values: The apparent digestibility and nutritive value data are represented in Table 2. The results indicated that the apparent digestibility of DM, NDF, ADF, TDN and DCP was increased significantly (p<0.05) using ration containing of tomato pomace silage comparing to the ration containing clover. However, when the ration with ensiled tomato pomace were fed, the digestibility of crude protein and cellulose were significantly (p<0.05) decreased comparing to the control ration. The apparent digestibility of OM, CF, EE and hemicelluloses was not influenced by the composition of the rations.
The positive effects of TPS on some nutrients digestibility in the present study are consistent with those of Abdollahzadeh et al. (2010), who reported that feeding on ensiled mixed tomato and apple pomace to replace alfalfa hay for Holstein dairy cows led to increase significant (p<0.05) DM and OM digestibility between rations and improved other nutrients, CP and NDF without any significant differences. Moreover, Yuangklang et al. (2010) found that the replacement of dietary soybean meal by dried tomato pomace in beef cattle rations did not affect apparent, total gastro-intestinal tract digestibility of NDF and ADF; however, apparent digestibility of crude protein was lowered by the rations containing tomato pomace.
| Table 2: | Effect of experimental rations on nutrients digestibility and nutritive values |
| Means in the same row with different superscript are significantly different (p<0.05) | |
Within an in vitro study, Besharati et al. (2008) reported that low gas yield for TP in initial incubation times compared to the other test feeds was resulted due to high content of slowly fermented carbohydrates in TP. Tomato pomace had high level of NDF and it needs more time to attachment of microorganism. Also, an increase in colonic fermentation and bacterial growth would raise the fecal excretion of nitrogen which in turn would lower apparent total gastro-intestinal tract digestibility of crude protein (Heijnen and Beynen, 1997). Also, the heat treatment of by-product may be change in protein structure which can modify protein digestibility (Ziaei and Molaei, 2010).
In the current study imply that the magnitude of rumen fermentation or rather the number of ruminal bacteria was positively influenced by the amount of tomato pomace in the ration and thereby improving of the nutritional value of the ration.
Milk yield and its composition: The overall mean of milk yield (kg/head/day) and composition (%) results affected by experimental rations are illustrated in Table 3. Actual milk yield for both groups were not significantly (p>0.05) affected by treatments. However, 7% fat corrected milk was significantly (p<0.05) increased by 14% in buffaloes group in response to dietary tomato pomace silage. The tomato pomace silage group had the highest (p<0.05) milk fat content (8.55%) than another group. Other milk constituents; protein, lactose, Total Solids (TS), Solids Non-Fat (SNF) and minerals did not affected by experimental rations. The results of current study are agreed with those reported by Abbeddou et al. (2011a), Romero-Huelva et al. (2012) and Abbeddou et al. (2014). More references demonstrated the improving NDF and ADF digestibility which rumen bacteria can use to produce acetate by fermentation and leading to proper condition for milk fat synthesis (Church, 1988; Del Valle et al., 2006; NRC., 2001). Also, the feeding on ration contents in more than 40% of tomato pomace and corn silages may be attributed in enhance production of acetate.
In contrast, Shdaifat et al. (2013) found that no differences for milk production or milk composition of lactating Awassi ewes fed a conventional ration or rations containing tomato pomace ration. Also, Romero-Huelva et al. (2012) and Abbeddou et al. (2014) found a trend towards lower milk yield with tomato pomace, too, even though it was included at aproportion of only 12.5 and 30% in DM, respectively.
| Table 3: | Effect of experimental rations on milk yield and milk composition |
| Means in the same row with different superscripts are significantly different (p<0.05) | |
Effect of experimental rations on milk fatty acids profiles: The fraction of milk fat affected by replacing the clover on the animal’s rations by tomato pomace silage is presented in Table 4. The results are presented as a relative percent. Data of Table 4 clearly showed that C8:0, C10:0, C12:0, C14:0, C14:1, C15:0, C15:1, C16:0 and C16:1 were significantly decreased (p<0.05) by the ration contacting tomato pomace silage comparing to ration contacting clover. However, the feeding lactating buffaloes with rations contain tomato pomace silage led to increasing C18:0, C18:1, C18:1n7, C18:2n6, C18:4n3, C20:0 and C20:4 and it was significant (p<0.05). On the other hand, the short and medium-chain fatty acids lower in proportions in this group fed tomato pomace silage, while polyunsaturated fatty acids, except C18:3 ω3 α-linolenic acid did not affect by both rations, seemed to be high (p<0.05) with TPS group than other. The previous results are in accordance with those of Abbeddou et al. (2011b), who reported that the rations containing tomato pomace with their elevated fat content, led to higher (p<0.05) proportions of polyunsaturated fatty acids versus short and medium-chain fatty acids in milk fat. Also, similar results in recent study to Abbeddou et al. (2014), the authors found also that tomato pomace was particularly rich in long chain-fatty acids than short and medium-chain fatty acids. On the other hands, the results of other studies (Romano et al., 2010; Romero-Huelva et al., 2012) disagreed quite strongly with those of Abbeddou et al. (2011b), Abbeddou et al. (2014) and the present study.
Some researchers suggested that unsaturated fatty acids may inhibit their de novo synthesis in the mammary gland (Bauman and Griinari, 2003) but they may also simply have been diluted by C18 fatty acids in milk (Bodas et al., 2010), others said probably by C18:0 desaturation in the mammary gland, has to be assumed as a consequence of the greater metabolic supply with 18:0 with tomato pomace (Chilliard et al., 2007; Abbeddou et al., 2011b).
| Table 4: | Effect of the experimental rations on fatty acids profile of milk |
| NIFA: Non identified fatty acids, Means in the same row with different superscripts are significantly different (p<0.05) | |
Effect of the experimental rations on amino acids profile: The results of milk protein amino acids fraction are illustrated in Table 5. The essential amino acids were not significantly affected by R2 (feeding on tomato pomace silage), except threonine and leucine which they were significantly (p<0.05) decreased comparing to R1. In addition, limited amino acids content for dairy cows (methionine and lysine) were did not significantly (p>0.05) affect by feeding with tomato pomace silage in spite of its high content of lysine according to the reports by Al-Betawi (2005) and NRC (2001). In context, some of nonessential amino acids (NEAA) such as (Aspartic acid, serine, proline, tyrosine and cystine) were significantly (p<0.05) decreased by tomato pomace feeding comparing to clover feeding; however, other nonessential amino acids (glutamic acid, glycine and alanine) were not significantly (p>0.05) affected by tomato pomace feeding. There are no enough reports about the effect of tomato pomace feeding on amino acids composition in lactating buffalo's milk. But, studies have revealed that a very valuable constituent of tomato pomace to the amino acids, an amino acid analysis of seeds indicated that approximately 60% of the protein results from amino acids, due to their higher contents of most essential amino acids (Knoblich et al., 2005). The reports of NRC (2001) demonstrated that amino acids compositions of tomato pomace were very valuable to arginine, leucine and lysine.
While, the amino acids constituents of tomato pomace used to the current study may be affected by degradation and partial hydrolysis of certain proteins duration provide it for high temperature processing of tomatoes that due to increases the level of free amino acids and this agreement reported by Ziaei and Molaei (2010).
| Table 5: | Effect of the experimental rations on amino acids profile of milk |
| Means in the same row with different superscript are significantly different (p<0.05), EAA/NEAA: Essential amino acids: Non-essential amino acids ratio | |
Effect of experimental rations on feed intake, feed conversion and economical study: The efficiency of feed utilization expressed as amounted of DM, TDN and DCP required producing 1 kg 7% FCM is presented in Table 6. Results indicate that tomato pomace silage containing ration (R2) resulted a significantly improvement feed utilization as TDN and DCP/kg 7% FCM by 15.38 and 16.07% for TDN and DCP, respectively comparing to feeding R1. The better efficiency of combination of tomato pomace silage with CFM, corn silage and rice straw might be attributed to the high digestible values of all nutrients in the related ration (R2) as shown in Table 2. These results are in agreement with those of Abdollahzadeh et al. (2010), who found a tendency towards better feed conversion with feeding lactating buffaloes/cow tomato pomace silage.
Economical evaluation of milk production as the result of replacement clover with tomato pomace silage is presented in Table 6. Daily feed cost decreased with including tomato pomace silage (R2) as the result of its low price compared to clover. Buffaloes fed R2 contained tomato pomace silage recorded the highest economic efficiency which were higher by 24%, than those fed R1.
Furthermore, economical efficiency as the ratio between the price of 7% FCM produced/costs of feed intake showed significant increase (p<0.05) with substituting clover in control ration (R1) by tomato pomace silage in R2. Economic efficiency of lactating buffaloes fed R1 and R2 were 0.55 and 0.44, respectively.
| Table 6: | Effect of experimental rations on feed intake, feed conversion and economical study |
| Prices: CFM (2.50 LE kg-1), rice straw (0.3 LE kg-1), clover (0.22 LE kg-1), milk (6.50 LE kg-1), corn silage (0.35 LE kg-1) and tomato pomace silage (0.19 LE kg-1). Revenue: Money output-money input, Economical efficiency: Money output/money input | |
CONCLUSION
Results obtained indicated that substitution of clover by tomato pomace silage as a forage had a positive effect on nutrients digestibility and nutritive values of the experimental rations. Actual milk yield and milk composition did not show differences but there was a significant increase in 7% FCM and milk fat percent. Polyunsaturated fatty acids in milk were higher with tomato pomace silage ration. Amino acids contents were negatively affected by feeding of tomato pomace silage. Economic efficiency of ration contained tomato pomace silage improved by 25% compared with control ration without any adverse effect on performance of lactating buffaloes.