Passion fruit (Passiflora edulis) peel as feed for ruminants in Vietnam: use of passion fruit peel silage in the diet of dairy cattle

Tran Hiep, Bui Quang Tuan, Nguyen Hung Son, Le Van Ha¹ and Nguyen Xuan Trach

Vietnam National University of Agriculture, Hanoi, Vietnam
nxtrach@vnua.edu.vn
¹ Tay Bac University, Son La, Vietnam

Abstract

Two on-farm feeding trials were carried out to test response of heifers and milking cows to rations using passion fruit peel (PFP) silage to replace whole crop maize silage (CTL) as an ingredient of the ration. PFP was madeinto silage according to a formula consisting of 75% PFP, 20% dry maize cobs, and 5% molasses. It was used to replace 50% (PFS50) or 100% (PFS100) of the maize silage in a total mixed ration, normally formulated by the farm (control ration) for Holstein heifers or milking cows. In each feeding trial, a total of 15 animals were randomly allocated to 3 groups of 5 each to be fed 3 rations. Results showed almost no significant differences in feed intake, feed conversion ratio (FCR), changes in body weight (BW), milk yield (MY) and milk quality were found among groups in the trials. It was therefore concluded that PFP silage can be used to replace whole crop maize silage in the ration without losses in growth performance (heifers) or milk yield and milk quality (milking cows).

Keywords: byproduct, cows, feeding, heifers, milk

Introduction

Passion fruit (Passiflora edulis) peel is a byproduct with large volumes from passion fruit processing (Hiep et al 2020). However, it has been mostly left as a waste, causing serious environmental problems, despite of several studies showing that passion fruit peel can be used as a good feed (Azevêdo et al 2012; Santos-Cruz et al 2013; Alves et al 2015; Sena et al 2015a,b). In Vietnam, the passion fruit industry has dramatically grown recently but also raised concerns of environmental pollution. In order to make use of passion fruit peel as feed, studies on quantification, analysis of chemical composition and making silage of this byproduct have been conducted with encouraging results. A conclusion was drawn that passion fruit peel can be made good silage according to a formula consisting of 75% passion fruit peel, 20% dry maize cobs, and 5% molasses (Hiep et al 2020). As a step to follow for later on practical application, the present study was designed to test if it was possible to use PFP silage to replace whole crop maize silage as an ingredient in the diets of heifers and milking cows.

Materials and methods

Study site and time

Two feeding trials were carried out on farm at Moc Chau Dairy Cattle Breeding Joint Stock Company located in the mountainous province of Son La, North West of Vietnam, from September 2018 to January 2019.

Materials

The two feeding trials were conducted on Holstein heifer and milking cow to test if it was possible to replace whole crop maize silage with PFP silage in their diets. Most of the feedstuffs used in the feeding trials (Table 1) were those normally used by the farm, except for PFP silage. Maize and elephant grass were grown by the farm. Whole crop maize was made into silage. Elephant grass was fed fresh after cutting. Molasses was bought from a local sugarcane factory. There were two types of concentrate, concentrate mix for heifers and concentrate pellets for milking cows, which were produced by the Company. The concentrates consisted of ground corn, ground cassava, ground soybean cake, ground rape cake, ground palm cake, palm oil, mineral-vitamin premix, NaHCO₃, lime, and common salt.

Fresh passion fruit peel was collected from a fruit processing company located nearby. It was made into silage according to a formula selected from the different formulae tried by Hiep et al (2020), viz. 75% PFP + 20% dry maize cobs + 5% molasses based on the weight of the ingredients as they were at the time of making silage. The PFP was chopped with a chopping machine into 1-2 cm in length. The dry maize cobs were ground with a grinding machine through a 0.5 cm sieve. All the ingredients were well mixed together and then compacted layer by layer with a tractor in concrete pits, which were then covered airtight. After 30 days of ensiling the silage was used as an ingredient of the rations in the feeding trials on heifers (Table 2) and milking cows (Table 3).

Feeding trial on heifers

A total of 15 Holstein heifers 6-7 months of age with an average body weight of 172 ± 3.42kg were allocated to 3 groups of 5 each according to a completely randomized design to be fed 3 different rations (Table 2). One group was fed the ration without PFP as normally used by the farm (CTL). The second group was fed PFS50, in which 50% of the maize silage in the control ration was replaced with PFP silage. The third group was fed PFS100, in which 100% of the maize silage in the CTL ration was replaced with PFP silage. Except for the two silages, which accounted for 65% dry matter (DM) of the rations, all the other ingredients (elephant grass, concentrate mix) were the same for all groups. Chemical composition in terms of DM, crude protein (CP), crude fiber (CF), and metabolizable energy (ME) were almost the same for the three rations.

The main period of experiment was 12 weeks after 2 weeks of adaptation. The animals were kept in individual stalls and fed twice daily at 8am and 4pm. Before each feeding, elephant grass was chopped into 1-2 cm in length and mixed thoroughly with all the other diet ingredients. The supplied amounts were adjusted so as to maintain the individual leftovers at around 10% of the total supplied. Water was supplied freely at all times.

Feeding trial on milking cows

A total of 15 Holstein cows in 2-3 months of lactation with an average milk yield of 19.4 ± 4.31 kg/day,  milk solid not fat (SNF) of 8.59 ± 1.98 %, milk fat of 3.54 ± 0.80%, and milk protein of 3.48 ± 0.76% were selected for the feeding trial. The cows were allocated to 3 groups of 5 each according to a completely randomized design to be fed 3 different rations (Table 3). One group was fed the ration without PFP as normally used by the farm (control ration). Two other groups were fed PFS50 and PFS100, in which PFP silage replaced 50% and 100% maize silage in the CTL  ration, respectively. Except for the two silages, which accounted for 40% DM of the rations, all the other ingredients were the same for all groups. Chemical composition in terms of DM, CP, CF, and ME were almost the same for the three rations.

The main period of experiment was 12 weeks after 2 weeks of adaptation. The animals were kept in individual stalls and fed around the times of milking. Before each feeding, elephant grass was chopped into 1-2 cm in length and mixed thoroughly with all the other diet ingredients. The supplied amounts were adjusted so as to maintain the individual leftovers at around 10% of the total supplied. One third of the morning or afternoon portion was supplied just before milking and the rest after milking. Water was supplied freely at all times.

Measurements

Feed intake:

Total feed offered, and refusals, were measured every day for each animal during the whole feeding trials to determine intake. Samples of feed offered and refusal were taken before the last morning feeding of each week. After homogenization, an amount of about 0.5kg of feed offered was taken for each cow and put into a plastic bag. Feed refusals were mixed well together, then an amount of 10% was taken into a plastic bag for each animal. All the feed and refusal samples were stored at -18^oC in freezers immediately after collection until the end of the experimental period. After thawing, the composite samples were made and then dried in a forced-ventilation oven at 60ºC for 72 h. Subsequently, they were processed in a knife mill with 1 mm sieve and stored in glass bottles at room temperature for later chemical analyses of DM, CP, CF, and EE according to the respective proximate methods of the AOAC (1990). ME was then calculated according to Wardeh (1981). Dry matter intake (DMI), ME intake (MEI), and CP intake (CPI) were calculated by difference between the amount offered and the amount left in refusals.

Body weight gain:

The heifers were weighed before the morning feeding on the first two days and the last two days of the trials using an electronic balance (RudWeight, Australia) to determine weight gain, which was calculated as the difference between the two average weights for each animal. In addition, intermediary weightings were performed in 4-week intervals throughout the experimental period to monitor the animal performance and identify any possible anomalies.

Milk yield:

The cows were milked twice daily starting at 6am and 3pm using a portable bucket milking machine (Bartech-Turkey). The amounts of milk from individual cows were weighed after milking using a 50 ± 0.3kg analog scale and recorded for the whole experimental period. Daily milk yield (MY) was calculated for each cow as sum of the morning and afternoon milk yields. Fat corrected milk yield (FCMY) was also calculated for the purpose of comparison among the groups.

Milk quality:

Fresh samples of milk from each cow were collected in the morning and afternoon milkings on 3 first consecutive days of week 3, 7, and 11. The samples were stored in 25 mL plastic tubes in freezers at -18⁰C before chemical analysis for fat, protein, and SNF at the Central Laboratory of the Faculty of Animal Science, Vietnam National University of Agriculture.

Statistical analysis

Data were statistically analyzed using Proc GLM in MINITAB software. The sources of variation were ration and error term. Tukey’s pairwise comparison was used to find significant differences between means at p <0.05.

Results and discussion

As can be seen in Table 4, body weights and weight gains of heifers were similar among the three rations. The similar changes in body weight can be explained by similar intakes of DM, CP and ME as well as their conversion ratios among the rations as shown in Table 5.

For milking cows, milk yields (MY and FCMY) and milk quality (SNF, fat, and protein) did not differ among the rations, although on the average there was some better milk yield and milk quality for the groups fed PFP silage (Table 6).

Table 7 shows that dry mater intake (DMI), ME intake (MEI) and crude protein intake (CPI) were almost the same for all groups. DMI in all groups reached nearly 3.4% BW, which is normal for milking cows at this stage of lactation (after milk peak). The conversion ratios of DM, ME and CP were not different among the groups. These similarities could explain the similar milk yield and milk quality among the three groups as shown in Table 6.

From the results of the two feeding trials it can be said that PFP silage is at least as good as whole crop maize silage as feed for dairy cattle. That may be due to the fact that PFP silage had good quality (Hiep et al 2020) with similar chemical composition and ME values compared with those of the whole crop maize silage as shown in Table 1. Therefore, PFP can and should be utilized to substitute maize silage wherever and whenever it is available to reduce feeding costs and minimize environmental pollution at the same time. Moreover, the formula of PFP silage making would pay the way for better utilization of dry corn cobs and molasses as locally available cheep byproducts for feeding dairy cattle.

The above results of the two feeding trials are in agreement with several previous studies on use of PFP as feed used for other types of ruminants. Sena et al (2015a) and Almeida et al (2019) show that dehydrated passion fruit by-product is a good option for partial replacement of sorghum silage (75%) as feed for lambs. In another experiment by Sena et al (2015b), PFP can substitute Tifton 85 (Cynodon spp.) in diets for Santa Inês × Dorper rams at approximately 30% without impairing performance and carcass traits. Especially, Alves et al (2015) report that steers fed passion fruit by-product showed higher feed intake, digestibility, and body weight gain than those fed sorghum silage. These all together indicate that PFP can be used in different ways as an excellent feed for ruminants.

Conclusions

• Fresh passion fruit peel silage (75% passion fruit peel + 20% dry maize cobs + 5% molasses on the basis of as used weights) can replace whole crop maize silage in rations for heifers and milking cows without any losses in growth performance (heifers) or milk yield and milk quality (milking cows), potentially reducing feeding costs as well as environmental pollution.

Acknowledgements

• The present study was supported under the Son La province funded project named “Applied study on improved utilization of dry maize cobs, sugarcane bagasse and passion fruit peel as feeds for dairy cattle in Son La province”.

References

Almeida J C S, Figueiredo D M, Azevedo K, Paixão M P, Ribeiro E G and Dallago G M 2019 Intake, digestibility, microbial protein production, and nitrogen balance of lambs fed with sorghum silage partially replaced with dehydrated fruit by-products. Tropical Animal Health and Production, 51, 619–627. https://link.springer.com/article/10.1007/s11250-018-1734-0

Alves G R, Fontes C A, Processi E F, Fernandes A M, Silva de Oliveira T and Glória L S 2015 Performance and digestibility of steers fed by-product of fresh passion fruit or sorghum silage, with and without concentrate supplementation. Revista Brasileira de Zootecnia, 44(9), 314-320. http://dx.doi.org/10.1590/S1806-92902015000900002

AOAC 1990 Official methods of analysis, 15th Edition. Association of Official Analytical Chemists, Washington DC.

Azevêdo J A G, Filho S C V, Detmann E, Pina D S, Paulino M F, Valadares R F D, Pereira L G R and Lima J C M 2012 In situ and in vitro degradation kinetics and prediction of the digestible neutral detergent fiber of agricultural and agro-industrial byproducts. Revista Brasileira de Zootecnia, 41(8), 1890-1898. http://dx.doi.org/10.1590/S1516-35982012000800013

Hiep T, Tuan B Q, Phuong L V, Sơn N H, Ha L V and Trach N X 2020 Passion fruit (Passiflora edulis) peel as feed for ruminants in Vietnam: Quantification, chemical composition and possibility to make silage. Livestock Research for Rural Development. Volume 32, Article #35. Retrieved February 7, 2020, from http://www.lrrd.org/lrrd32/2/trach32035.html

Santos-Cruz C L, Pérez J R O, Lima T R, Cruz C A C, Cruz B C C and Junqueira R S 2013 Centesimal composition and physicochemical parameters of meat from santa inês lambs fed with passion fruit peel. Semina: Ciências Agrárias, Londrina, 34(4), 1977-1988. doi: 10.5433/1679-0359.2013v34n4p1977

Sena J A B, Villela S D J, Pereira I G, Castro G H F, Mourthe M H F and Bonfa CS 2015a Intake, digestibility, microbial protein production, and nitrogen balance of lambs fed with sorghum silage partially replaced with dehydrated fruit byproducts. Small Ruminant Research, 129,18-24. doi: 10.1007/s11250-018-1734-0.

Sena J A B, Villela S D J, Santos R A, Pereira I G, Castro G H F, Mourthé M H F, Bonfá C S and Martins P G M A 2015b Intake, digestibility, performance, and carcass traits of rams provided with dehydrated passion fruit (Passiflora edulis f. flavicarpa) peel, as a substitute of Tifton 85 (Cynodon spp.). Small Ruminant Research, 129(Supplement C), 18–24. https://doi.org/10.1016/j.smallrumres.2015.05.005

Wardeh M F 1981 Models for Estimating Energy and Protein Utilization for Feeds. All Graduate Thesis and Dissertations, Utah State University. https://digitalcommons.usu.edu/etd/4556

Received 5 March 2020; Accepted 7 March 2020; Published 1 April 2020

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