Livestock Research for Rural Development 15 (1) 2003

Citation of this paper

N balance studies in young Mong Cai and Large White pigs fed high fibre diets based on wheat bran 

J Ly, Chhay Ty and Pok Samkol 

The Ecological Farm, University of Tropical Agriculture Foundation
Chamcar Daung, Dangkor District, PO Box 2423, Phnom Penh 3, Cambodia
jlyca@yahoo.com;    samkol@utafoundation.org

Abstract 

A total of 16 castrate male pigs [Mong Cai (MC) or Large White (LW)] with an average weight of 20 kg were used in a random two-block design to study N utilization from a high fibre diet consisting of wheat bran as the major dietary component (68% in dry basis). Daily feed consumption was 40 g DM/kg body weight and crude protein (Nx6.25) of the diet was 18% in DM.  

There was no effect of genotype on total tract digestibility for DM, organic matter, crude fibre and NDF but MC pigs digested  less N than LW animals. Faecal pH values were lower and short chain fatty acids and ammonia tended toward a higher output in MC pigs than in LW.  N retention was lower in MC than in LW pigs when expressed as a proportion of live weight or of N intake.  This trend was not apparent for N retention as proportion of N digested..

The results from the present experiment suggest that the N requirement of Mong Cai pigs may be lower than what is recommended for "improved" genotypes selected for lean meat production.  

Key words:  Genotype, Large White, Mong Cai, N balance,  pigs 
 

Introduction  

Experimental evidence has been accumulated suggesting that the scheme of N utilization in Mong Cai pigs is somewhat different from that observed in improved pig genotypes selected for lean meat traits (Bun Tean 2002; Nguyen Thi Thuy and Ly 2002; Chiv Phiny et al 2002). The Mong Cai breed has probably originated in the Red River basin, in North Vietnam (Molenat and Tran 1991), and its population size is considerable in Indochina, mainly in Vietnam.  

A somewhat similar trend in N utilization has been observed in another Asian breed, the Meishan pigs from China, when compared to European Large White animals (Février et al 1990; Guohai et al 1990, cited by Aumaitre et al 1992; Kemp et al 1991). This could explain the apparent lower efficiency of N utilization by Mong Cai (and similar unselected genotypes) for protein accretion for growth purposes, when rations are formulated according to the needs of "improved" breeds. Such improved genotypes, which been selected for a high protein to fat ratio, are usually fed to express the maximum potential of growth of lean body mass.  In Europe, Whittemore et al (2001) have recently directed attention towards the relationship between the nutrient requirements by the pig, and the effective use of these nutrients. 

The aim of the present experiment was to obtain additional information about the characteristics of some digestive processes and N balance in Mong Cai  as compared to Large White pigs, kept in a common environment, in terms of feeding management and high air temperature. 
 

Materials and Methods 

Eight Mong Cai and eight Large White castrate male pigs, with an average weight of 20 kg,  were allocated in a random two-block design to study N utilization from a high fibre diet consisting of wheat bran as the major dietary component. The Mong Cai pigs were of Vietnamese origin (from Thu Duc, near Ho Chi Minh City) and the Large White pigs were of commercial origin, locally available in the Phnom Penh market. Both types of animals had been born from parents raised in the University pig herd, at the Ecological Farm. 

The diet was composed (% DM basis) of wheat bran 68.0,  maize bran 20.0, dried fresh water fish 10, vitamin and mineral premix 2.0. The vitamin and mineral supplementation was according to NRC (1998) recommendations. Details of the chemical composition of the ingredients and the diet are in Table 1. Daily feed intake was adjusted to 40 g/kg of live body weight, which was close to ad libitum based on previous observations. The daily feed allowance was given in a meal form twice daily (7:00 and 13:00 h) in equal quantities. Fresh water was available through drinking nipples.  

The animals had a five-day adaptation to the diets. During the adaptation period, feed consumption was adjusted to a level with no feed refusals. Thereafter, quantitative collection of faeces, urine and any feed residue were made during another five days. During the entire 10-day period, the animals were housed individually in metabolism crates designed for quantitative collection of faeces and urine separately. These crates were in an open stable without walls. Urine was collected in covered plastic buckets, under enough H₂SO₄ solution to keep the liquid at pH below 4. 

The DM content of feeds and faeces was determined according to Undersander et al (1993) by microwave radiation until constant weight, and N in feeds, faeces and urine was as indicated by the A0AC (1990) the wet oxidation Kjeldahl procedure. The content of cell walls (NDF) in the samples was determined according to Van Soest et al (1991). The gross energy value of feed ingredients and the diet was calculated according to the Nehring and Haenlein (1973) formula.  Water holding capacity of feed ingredients was determined by the filtration technique described by Tsaras et al (1998) as adapted by Ly (2003), by using during five minutes a gentle vacuum originated from a commercial dust aspirator connected to a vacuum flask. 

The pH value in fresh faeces was determined with a glass electrode fitted to a digital pH meter. In addition, faecal concentrations of short chain fatty acids (SCFA) and NH₃ were estimated in fresh faecal material filtered through three sheets of cotton after suspending the samples in distilled water (1:4 by weight). The samples were mixed in the ratio of 1:1 (by volume) with a saturated solution of MgSO₄ in H₂SO₄ and the resulting acid product of steam distillation titrated, following the method outlined by the standard procedure of Pennington (1952; quoted by Ly 1986).  In this particular case, an aliquot of the faecal filtered slurry was steam distilled  after mixing with NaOH 40% in the ratio 1:5 (by volume) as recommended in the standard Kjeldahl procedure,  and then titrated by the acid-base method. 

The indicators of daily faecal output were calculated as described by Ly et al (1998). All analyses were conducted in duplicate. 

Means between treatments were compared by the standard t-test (Steel and Torrie 1980) following ANOVA analysis using the Minitab program software (Ryan et al 1992). Regression analysis was employed in the required cases. 

Results

General 

Average air temperature during  the trial was 35.0 ± 3.5^oC as measured every day at 12:00 hours. The animals did not show any symptom of discomfort at any moment and feed refusals were minimal, perhaps due to the fact that a rather low consumption of feed was selected during the experiment (the level had been fixed according to recorded intakes by the Mong Cai pigs, which is less than has been observed in Large White pigs of the same live weight). The pigs were always in positive live weight balance, with an average daily gain during the ten-day period of 200 ± 35 g/day.

Digestive indices 

There was no effect of genotype on faecal excretion of fresh material and water, the values of which were high as expected from the high water holding capacity of the diet (Table 2).  The Large White pigs had a higher faecal pH than Mong Cai animals. On the other hand, faecal concentration and output of metabolites tended to be higher (a trend for NH₃ (P<0.10) and higher for SCFA (P<0.05) in the Mong Cai than in the Large White pigs. There was a great variability in the faecal indices, which implies that large numbers of animals would be needed to demonstrate that the observed differences represented a true effect of breed.

In previous experiments, faecal output of SCFA and ammonia appeared to be inversely proportional to pH values in faeces from Mong Cai pigs ((Ly and Pok Samkol 2001; Ly 2003), and this phenomenum appeared to hold true for faecal SCFA and pH (P<0.08) on one hand, and for faecal ammonia and pH (P<0.04) on the other hand. At the same time a straight, negative relationship has previously been found between faecal output of these types of metabolites and organic matter digestibility (Ly 2003). A similar significant relationship (Table 3) was observed in the current study, which appeared to be stronger for ammonia than for SCFA output, and on the other hand, stronger for Large White than for Mong Cai pigs. 

Since it has been revealed that bacterial metabolism in pig's faeces is similar to that occurring in the terminal part of the gastrointestinal tract in this species (Williams et al 1998; Bauer et al 2001), it is possible to think that there exists certain influence, other than the dietary effect, on microbial activity in the large intestine of the pig due to the nature of the genotype under examination. In fact, Bruininx et al (2002) observed a noticeable influence of piglet genotype on SCFA and ammonia concentration in large intestinal digesta. An increase in microbial activity in caecum and colon of Mong Cai pigs, through a shift of bacterial balance to enhance the cellulolytic bacteria population (Varel et al 1984; Varel 1987), could support an increase in degradation of the fibrous fractions of the diet, as data from the present experiment could indicate. As it is well known, the large intestine of the pig is the main site of the alimentary canal for fibre degradation (Bach Knudsen and Jorgensen 2001).  An increase in activity of the large intestinal microbiota could occur too in organs susceptible to be further anatomically adapted to room bulky feeds (Low 1985, 1993; Kyriazakis and Emmans 1995). 

There was no significant influence of breed on DM and organic matter digestibility (Table 4), which was relatively high, in spite of a high NDF content in the diet that could in turn negatively affect digestive indices, as it has been claimed elsewhere (Fernández and Jorgensen 1986; Close 1993; Le Goff et al 2002). Digestibility of NDF and crude fibre were relatively high too in both breeds taking into account the highly fibrous nature of the rations, with a very slight inclination, although not significant (P>0.10) for Mong Cai pigs to better digest several fibre fractions as compared to the Large White animals. In this connection, it has been found that total tract digestibility of hemicellulose and cellulose is not higher than 45 and 35% respectively for wheat bran in Large White pigs (Chabeauti 1991; Chabeauti et al 1991). 

There are conflicting results concerning fibre fraction utilization by local pigs from the Far East of Asia. Aumaitre et al (1992) did not find differences between improved European on one hand and Chinese breeds on the other in digestive capacity for utilization of dietary fibre.  In a previous experiment with Mong Cai pigs (Nguyen Thi Thuy and Ly 2002), it was observed a non significant improvement of NDF digestibility as compared to Large White animals. 

Balance of N 

Several indices of N balance indicated that Mong Cai utilized less dietary N than Large White pigs (Table 5). There was a similar mean daily N intake in both breeds, but Mong Cai showed a high variability for this index.  Faecal excretion of N was higher (P<0.05) in Mong Cai animals than in the Large White, and this phenomenum determined a significantly higher digestibility (P<0.01) for pigs of the Large White breed. These results are in accordance with others comparing these two same genotypes (Nguyen Thi Thuy and Ly 2002). 

It was found that 40.8% of total N excretion was via faeces in the Mong Cai pigs whereas the same index was only 33.8% in the Large White animals (Figure 1). As it can be clearly deduced, urine was the main route of N elimination in both breeds eating a highly fibrous diet. 

A trend was found for total excretion of N to be higher in the Mong Cai animals when this index was compared to that of Large White pigs. In consequence, animals from the Large White genotype had a significantly higher N retention in terms of the daily total amount retained (P<0.05) or related to the N intake in percentage (P<0.01). N retention in Mong Cai pigs (6.7 g/day) accounted for 83.6% of the same index for Large White pigs (7.9 g/day). This same trend was not apparent for N retention expressed as percentage of digested N (P<0.26) between both genotypes studied. However, the efficiency of utilization of digested N accounted for 93.7% in compared values for Mong Cai and Large White pigs.

Results concerning the effect of genotype on N balance are in accordance with other previous studies (Bun Tean 2002; Chiv Phiny et al 2002) indicating a lower N utilization by Mong Cai pigs as compared to other improved breeds. The data from the current investigation are in accordance too with a similar trend previously observed with Meishan pigs as compared to Large White (Février et al 1990; Kemp et al 1991), or with Jiaxing pigs if compared to Jiaxing x Landrace animals (Guohai et al 1990; cited by Aumaitre et al 1992). 

Conclusions

Results from the present experiment support the hypothesis that N requirement of Mong Cai pigs must probably be lower than that recommended for certain improved genotypes for lean meat. 

More research is needed in order to clarify the pattern of microbial digestion of N in the large intestine of pigs fed high levels of fibrous materials, with emphasis on the nature of the pig's genotype and the botanical origin of the dietary fibre. 

Acknowledgements

This publication is an output from a collaborative research work carried out by members of the staff of the University of Tropical Agriculture Foundation, Cambodia, and the Swine Research Institute at Havana.

Thanks are given to the MEKARN project (supported by SIDA-SAREC of Sweden), for partial funding of the current investigation. The authors are grateful to Dr. Claude Février, formerly from the Swine Research Station at INRA, Rennes, for his support in literature search and comments.

References

AOAC 1990 Official Methods of Analysis. Association of Official Analytical Chemists. 15th edition (K Helrick, editor) Arlington p 1230

 

Aumaitre A, Peiniau J and Février C 1992 Digestive peculiarities of the Chinese pig. Physiological and nutritional consequences of dietary non starch polysaccharides. Proceedings of the International Symposium on Chinese Pig Breeds (Chen Rusheng, editor). Northeast Forestry University Press. Harbin p 247-250

 

Bach Knudsen  K E and Jorgensen H 2001 Intestinal degradation of dietary carbohydrates - from birth to maturity. In: Digestive Physiology in Pigs (J E Lindberg and B O Oglem editors) CAB Publishing. Wallingford p 109-120

 

Bauer E, Williams B A, Voigt C, Mosenthin R and Verstegen M W A 2001 Microbial activities of faeces from unweaned and adult pigs, in relation to selected carbohydrates. Animal Science 73:313-322

 

Bruininx E M A M, Schellingerhout A B, Lensen E G C, Van der Peet-Schwering C M C, Schrama J W, Everts H, Den Hartog L A and Beynen A C 2002 Associations between individual food intake characteristics and indicators of gut physiology of group-housed weanling pigs differing in genotype. Animal Science 75:103-113

 

Bun Tean 2002 MSci Thesis. University of Tropical Agriculture Foundation, Royal University of Agriculture. Phnom Penh.

 

Chabeauti E 1991 PhD Thesis. Université de Rennes. Rennes, France pp 150

 

Chabeauti E, Noblet J and Carré B 1991 Digestion of plant cell walls from four different sources in growing pigs. Animal Feed Science and Technology 32:207-213

 

Chiv Phiny, Preston T R and Ly J 2002 Mulberry (Morus alba) leaves as protein source for young pigs fed rice based diets. Digestibility studies. Livestock Research for Rural Development 15(1): http://www.cipav.org.co/lrrd/lrrd15/1/phin151.htm

 

Close W H 1993 Fibrous diets for pigs: In: Animal production in developing countries (M Gill, E Owen, G E Pollot and T L G Lawrence, editors) British Society of Animal Production Occasional Publication No 16. London p 107-115

 

Fernández J A and Jorgensen J H 1986 Digestibility and absorption of nutrients as affected by fibre content in the diet. Quantitative aspects. Livestock Production Science 15:53-64 

 

Février C, Bourdon D and Aumaitre A 1990 Effects of levels and source of dietary fibre on digestive utilization of the diet and growth performance in Large White and Meishan pig. Chinese Pig Symposium (M Molenat and C Legault, editors). INRA. Toulouse p 233-238.

 

Kemp B, Den Hartog A, Klok J J and Zandstra T 1991 The digestibility of nutrients, energy and nitrogen in the Meishan and Dutch Landrace pigs. Journal of Animal Physiology and Animal Nutrition 65:263-267

 

Kyriazakis I and Emmans G C 1995 The voluntary feed intake of pigs given feeds based on wheat bran, dried citrus pulp and grass meal, in relation to measurements of food bulk. British Journal of Nutrition 73:191-207

 

Le Goff G, Van Milgen J and Noblet J 2002 Influence of dietary fibre on digestive utilization and rate of passage in growing pigs, finishing pigs and adult sows. Animal Science 74:503-515

 

Low AG 1985 Role of dietary fibre in pig diets. In: Recent advances in animal nutrition (W Haresign and D J A Cole, editors) Butterworths. London p 87-112

 

Low A G 1993 Role of dietary fibre in pig diets. In: Recent developments in pig nutrition (D J A Cole, W Haresign and P C Gansworthy, editors). Nottingham University Press. Nottingham p 137-162

 

Ly J 1986 Large intestine digestion of pigs fed molasses. 5. VFA production. Cuban Journal of Agricultural Science 20:41-53

 

Ly J 2003 The effect of methionine on digestion indices and N balance of young Mong Cai pigs fed high levels of ensiled cassava leaves. Livestock Research for Rural Development 15(1): http://www.cipav.org.co/lrrd/lrrd15/1/ly151.htm

 

Ly J, Diéguez F J, Martínez R M and García A 1998 Digestion of a diet very high in fibre in Cuban Creole pigs. Animal Feed Science and Technology 72:297-302

 

Ly J and Pok Samkol 2001 Nutritional evaluation of tropical tree leaves for pigs. Desmanthus (Desmanthus virgatus). Livetock Research for Rural Development 13(4): http://www.cipav.org.co/lrrd/lrrd13/4/ly134a.htm

 

Molenat M and Tran T T 1991 La production porcine au Vietnam et son amélioration. World Animal Review 68(3):26-36

http://www.fao.org/ag/aga/agap/frg/feedback/war/u4900b/u4900b0a.htm

 

Nehring K and Haenlein G W F 1973 Feed evaluation and ration calculation based on net energy_FAT. Journal of Animal Science 36:161-181

 

Nguyen Thi Thuy and Ly J 2002 A short-term study of growth and digestibility indices in Mong Cai pigs fed rubber seed meal. Livestock Research for Rural Development 14(2): http://www.cipav.org.co/lrrd/lrrd14/2/thuy142.htm

 

NRC 1998 Nutrient Requirement of Swine. National Academy of Science. 9th edition. National Academy of Science Press. Washington D C

 

Pok Samkol and Ly J 2001 Nutritional evaluation of tree leaves for pigs. Flemingia (Flemingia macrophylla). Livestock Research for Rural Development 13(5): http://www.cipav.org.co/lrrd/lrrd13/5/samk135.htm

 

Ryan B F, Joiner B L and Ryan T A 1992 Minitab handbook (2nd edition) PWS-Kent Publishing Company. Boston

 

Steel T G D and Torrie J H 1980 Principles and Procedures of Statistics: a Biometrical Approach. McGraw-Hill Book Company (second edition) Toronto pp 481

 

Tsaras L N, Kyriazakis I and Emmans G C 1998 The prediction of the voluntary feed intake of pigs on poor quality foods. Animal Science 66:713-723

 

Undersander D, Mertens D R and Theix N 1993 Forage analysis procedures. National Forage Testing Association. Omaha pp 154

 

Van Soest P J, Robertson J B and Lewis B A 1991 Methods for dietary fiber, neutral detergent fiber and non starch polysaccharides in relation to animal nutrition. Journal of Dairy Science 74:3583-3593

 

Varel V H 1987 Activity of fiber-degrading micro-organisms in the pig large intestine. Journal of Animal Science 65:488-496

 

Varel V H, Pond H G and Yen J T 1984 Influence of dietary fiber on the performance and cellulase activity of growing-finishing swine. Journal of Animal Science 59:388-393

 

Williams B A, Voigt C and Verstegen M W A 1998 The faecal microbial population can be representative of large intestinal microfloral activity. Proceedings of the British Society of Animal Science p 165

 

Whittemore C T, Green D M and Knap P N 2001 Technical review of the energy and protein requirements of growing pigs: energy. Animal Science 73:199-205

 

 

 

Received 19 November 2002; Accepted 12 December 2002

 

Go to top