- Email: [email protected]
Adjustments of the protein level for slaughter pigs and supplementation with lysine and methionine
Animal Feed Science and Technology, 1 (1976) 619--629 619 © Elsevier Scientific Publishing Company, Amsterdam -- Printed in The Netherlands
A D J U S T M E N T S O F T H E P R O T E I N L E V E L F O R S L A U G H T E R PIGS A N D S U P P L E M E N T A T I O N WITH LYSINE AND METHIONINE
B. LAKSESVELA Department of Animal Husbandry and Genetics, The Veterinary College of Norway, Oslo (Norway)
(Received January 15th, 1976)
ABSTRACT Laksesvela, B., 1976. Adjustments of the protein level for slaughter pigs and supplementation with lysine and methionine. Anita. Feed Sci. Technol., 1 : 619--629. In two replicate experiments, pigs were fed on a diet in which protein was progressively reduced as they grew from 20 to 70 kg, and thereafter on a cereal mixture alone (treatment VPC), or on a diet in which the protein content was the same from beginning to slaughter, at 95 kg live weight (treatment FPC). Diet VPC resulted in statistically faster growth and better feed efficiency than FPC. Diet VPC, with 0.12% lysine added to the cereal component (VPCL), significantly improved the growth rate in comparison to both VPC and FPC, and also feed efficiency as compared to FPC. Methionine added at a level of 0.1% instead of lysine (VPCM) did not produce any improvement. Carcass quality was not significantly affected by the various treatments. Compensatory growth was not visible on FPC, which was deficient in protein in the beginning and excessive later.
INTRODUCTION It is stated a l m o s t a x i o m a t i c a l l y t h a t y o u n g , fast-growing animals require a higher p r o t e i n level in their feed t h a n older animals. The same applies to minerals and vitamins, for w h i c h the r e q u i r e m e n t s are fairly well k n o w n . These s t a t e m e n t s are based o n n u m e r o u s e x p e r i m e n t s in various countries. It has, h o w e v e r , been argued r e c e n t l y t h a t adjusting the p r o t e i n level in the feed a c c o r d i n g t o live weight or age is n o w less i m p o r t a n t for slaughter pigs. One basis for this a r g u m e n t is t h a t m o d e r n pigs are capable o f d e p o s i t i n g p r o t e i n at a high rate over a m u c h wider range o f b o d y weight t h a n the older type. A n o t h e r a r g u m e n t is t h a t we can m a k e use o f so-called c o m p e n s a t o r y g r o w t h , m e a n i n g t h a t slaughter pigs can m a k e up later for deficiencies in the early p a r t o f the rearing period, p r o v i d e d t h a t t h e y get sufficient o f t h e deficient n u t r i e n t s later. The a b o v e e x p l a n a t i o n s were p u t f o r w a r d w h e n FrSlich and T h o m k e {1969} o b t a i n e d equally g o o d results with adjusted and u n a d j u s t e d p r o t e i n
620 (and vitamin and mineral) levels from 20 to 90 kg live weight. Compensatory growth was recorded, as was the case in earlier Danish experiments (Madsen, 1964). The same tendency appeared vaguely in a preliminary Norwegian test (Robstad and SkrSvseth, 1973). All these authors found that no adjustments were as good as frequent adjustments, under the conditions of their experiments. Contrarily, Laksesvela and Slagsvold (1974, 1975) registered significantly faster growth and better feed utilization in three replicated tests when adjusting protein, vitamin and mineral levels according to live weight as compared to no adjustments. Regulating the nutrient levels only once, from higher to lower levels at 60 kg live weight, gave intermediate results. Total consumption of protein was approximately the same on the three different regimens. Similar results have been found with gilts reared for breeding purposes (Laksesvela, unpublished). The system prescribing a fixed allowance of a high-protein mixture from start to slaughter does, however, not work satisfactorily today, because cereals often contain sufficient protein for pigs having reached a live weight of approximately 70 kg. After that stage protein concentrates should be expected to be superfluous. The present paper describes two replicate experiments in which a daily allowance of 0.35 kg high-protein mixture was withdrawn at a live weight of 70 kg. Thereafter, the pigs received only the basal feed, consisting of mixed cereals fortified with vitamins and minerals. Adjusting the protein level according to age provided the same total quantity of protein up to a live weight of approximately 80 kg as did only one mixture, but subsequently required less protein. Additions of lysine or methionine to the cereal mixture were also tried. EXPERIMENTAL Animals and housing Norwegian Landrace gilts and castrated males were reared on concrete floors in heated houses. Experiment 1 comprised three dietary treatments, each given to 7 group-fed pigs, and Experiment 2 four dietary treatments each given to 8 individually-fed pigs. The groups were as uniform as possible as to litter, sex and weight. The pigs were slaughtered at a live weight of approximately 95 kg. Dietary treatments and codes The treatment for which the protein content of the diet was varied according to the age of the pigs, by changing the proportions of protein mixture and cereal mixture, was called VPC. When lysine was added to its cereal mixture, the regimen was called VPCL, and with methionine added, VPCM. The treatment consisting of one diet, having a fixed ratio of protein concentrates to cereals, was designated FPC.
621
Composition of diets The constituents of diets VPC and FPC, and their nutrient content, are listed in Table I. All nutrients included in the table were determined by analysis, except for values of ME and digestible crude protein, which were calculated. The cereal mixture in VPCL was fortified with 0.12% L-lysine, and the cereal mixture in VPCM with 0.1% DL-methionine. Daily allowances of feed and the quantities they conveyed of certain nutrients at various live-weights are set out in Table II. Feed allowances were adjusted with an accuracy of 0.1 kg on the basis of weekly weighings. Daily feed rations were divided into two meals, after which water was offered according to appetite. RESULTS The various data from Experiments 1 and 2 are presented in Tables III and IV, respectively. In both experiments VPC was more favourable than FPC, and VPCL was better than VPC.
Daily weight gain Daily weight gain in the two experiments was, on the average, 670 g on VPC, 708 g on VPCL and 608 g on FPC. The smallest differences were significant at the 2--5% levels, the greatest at the 0.1% level. As all pigs were slaughtered at approximately 95 kg live weight, the faster gain reduced the rearing time. Pigs fed VPC required approximately 11 days less than those fed FPC, and those fed VPCL approximately 5 days less than on VPC.
Feed efficiency Feed consumed per unit gain (kg/kg) was on average 3.25 for VPC, 3.09 for VPCL and 3.39 for FPC. Statistical analyses could be carried out only for the individually-fed pigs in Experiment 2, VPC and VPCL being significantly better than FPC at respective levels of 5% and 1%. Supplementation with methionine did not produce any improvement.
Carcass quality Carcass quality was good, being equal on the various diets, according to all measures taken. In addition, the general health of the pigs was similar for all the different diets.
622
TABLEI C o m p o s i t i o n a n d n u t r i e n t c o n t e n t o f diets VPC a n d FPC ( p e r c e n t e x c e p t w h e r e o t h e r w i s e stated) Protein m i x t u r e in VPC Constituents B l o o d meal, s p r a y dried Fish m e a l M e a t a n d b o n e m e a l - - low fat Soya bean meal -- extracted Oats, g r o u n d Barley, g r o u n d Rye, ground Sorghum, ground W h e a t offals Molasses Dicalcium phosphate Salt Mineral m i x a Micro m i n e r a l s b Vitamin mix c Methionine Total Nutrient content M.E. ( M c a l / k g ) Crude protein Dig. c r u d e p r o t e i n Fat C r u d e fibre Ca P NaC1 Lysine Methionine + cystine Isoleucine Threonine Available lysine
Cereal m i x t u r e in VPC
FPC
3 10 17 28.6 28 ---11.6 --1 -0.38 0.3 0.12
----20 60 17.7 ---1.3 0.12 0.8 -0.08 --
1.5 2 2 3.3 21 35.5 15 10 4 3.4 1.83 0.3 -0.07 0.1 --
100.00
100.00
100.00
2.76 35.2 29.5 4.1 7.0 1.9 1.4 1.24 2.22 1.37 1.45 1.41 1.70
2.93 10.2 8.4 1.9 4.8 0.53 0.57 0.28 0.39 0.44 0.40 0.37 0.27
2.89 14.4 11.5 2.7 4.7 0.78 0.73 0.41 0.64 0.64 0.54 0.52 0.46
a C o m p o s i t i o n : CaCO3, 46%; CaHPO4 • 2 H 2 0 , FeSO4, 0.82%; Z n S O , , 0.43%; CuSO4 • 5 H 2 0 , b C o n t a i n i n g : Mg, 11.9%; Fe, 3.3%; Mn, 6.0%; 41.5% CaCO3 as a carrier. C C o m p o s i t i o n per g r a m : 3 0 0 0 I.U. vit.A; 4 3 0 0.007 mg cobalamin.
34%; salt, 1 6 . 2 4 % ; MgO, 2%; M n O , 0.3%; 0.19%; CoSO4, 0 . 0 1 2 % ; KI, 0.01%. Zn, 3.9%, Cu, 1.1%; Co, 0 . 0 8 7 % ; I, 0 . 1 5 5 % ; I.U. vit.D; 20 m g vit.E; 3 m g r i b o f l a v i n ; a n d
623
O~
~ m
O~
C~
O,1
oO
o ~m
v
oO oO
0
I
I~
~
~
~=~
=
e~ ~
o~ ~ ° ~
.< Z
624
T A B L E III E x p e r i m e n t 1. G r o w t h rate, feed e f f i c i e n c y and carcass quality. Values c o r r e c t e d to 95 kg live weight and a dressing-out p e r c e n t a g e o f 70 (+ S.E.) Treatments
No. days f r o m 21.2 t o 95 kg Daily gain (g) Kg f e e d / k g gain Kcal M E / k g gain Back fat t h i c k n e s s ( m m ) Shoulder Midback Loin Side fat t h i c k n e s s ( m m ) Area o f m e a t c u t l e t ( c m 2) Fat firmness p o i n t s 0--15 Fat c o l o u r p o i n t s 0--15 Meat c o l o u r p o i n t s 0--5
VPC
VPCL
FPC
113.4 (±4.9) 653 (+46) 3.24 9.35
107.1 (±5.1) 697 (+42) 3.03 8.80
122.4 (-+6.3) 606 (-+39) 3.34 9.68
33.8 16.8 25.8 18.5 29.8
(+-2.3) (-+1.4) (-+2.2) (± 1.9) (+ 3.2)
31.6 17.1 27.1 18.8 30.2
(+2.0) (-+1.5) (-+2.3) (-+ 2.0) (± 2.9)
31.2 17.2 28.3 19.7 31.4
(_+2.1) (+ 1.8) (-+2.3) (-+ 2.2) (±3.3)
12.0 (± 1.0)
11.7 (+1.1)
11.9 (+1.3)
12.8 (-+0.9)
12.4 (-+1.3)
12.6 (-+1.2)
3.7 (±0.5)
3.6 (+0.4)
3.5 (+0.5)
T A B L E IV Experiment 2. Growth rate, feed efficiency and carcass quality. Values corrected to 95 kg live weight and a dressing-out percentage of 70 (+S.E.) Treatment
No. days from 17.7 to 95 kg Daily gain (g) Kg feed/kg gain Kcal ME/kg gain Back fat thickness (ram) Shoulder Midback Loin Side fat thickness (ram) Area of meat cutlet (cm 2) Fat firmness points 0--15 Fat colour points 0--15 Meat colour points 0--5
VPC
VPCL
VPCM
FPC
113.5 (-+4.8) 684 (+-38) 3.26 (-+0.18) 9.48 (+0.36)
109.5 (+3.9) 718 (±43) 3.15 (+-0.14) 9.15 (-+0.32)
116.1 (+-4.6) 666 {+48) 3.33 (+0.21) 9.68 (+-0.44)
126.3 (+-5.2) 609 (+-34) 3.43 (±0.13) 9.93 (-*0.31)
34.3 18.7 22.4 19.6 30.1
(± 2.1) (-+1.4) (+2.0) (+-1.7) (-+2.7)
34.2 17.7 22.6 21.5 32.2
(+-1.9) (±1.1) (-+2.2) (÷1.5) (±2.9)
32.1 16.9 19.6 20.5 30.3
(+-2.2) (+1.2) (-+1.8) (+1.8) (+-2.6)
34.3 17.4 21.4 20.7 30.0
(± 2.3) (+-1.3) (-+1.9) (+1.7) (+-3.1)
11.6 (+ 0.9)
11.8 (+-1.0)
11.7 (± 1.1)
11.4 (+-1.3 )
11.1 (+-0.%
12.1 (-+1.1)
11.1 (+1.2)
11.5 (± 1.0)
3.0 (-+0.4)
3.0 (+-0.3)
3.3 (+-0.5)
2.9 (±0.4)
625
Expenditure of protein T h e use o f VPC saved a p p r o x i m a t e l y 10, a n d V P C L 16% p r o t e i n as c o m p a r e d to FPC, while V P C L saved 6% in c o m p a r i s o n to VPC, c a l c u l a t e d as g o f d i e t a r y p r o t e i n p e r kg carcass p r o d u c e d . This saving t o o k place a f t e r the pigs h a d a t t a i n e d a live w e i g h t o f nearly 80 kg. T h e t o t a l i n t a k e s o f the various feed m i x t u r e s and o f p r o t e i n are set o u t in T a b l e V. CONCLUSIONS
Protein levels T a b l e II and Figure 1 s h o w t h a t VPC and FPC d i f f e r e d greatly as t o s u p p l y o f p r o t e i n , b o t h in t h e b e g i n n i n g a n d end o f the rearing period. When c o m paring t h e supplies o f digestible c r u d e p r o t e i n t o the r e q u i r e m e n t s s t a t e d b y B r e i r e m ( 1 9 7 5 ) it a p p e a r s t h a t VPC was s a t i s f a c t o r y , while FPC was d e f i c i e n t in t h e beginning, b u t c h a n g e d gradually to b e c o m e v e r y excessive later. Ca, P and NaC1 a n d v i t a m i n s varied also, b u t were n o t s u p p o s e d t o be d e f i c i e n t at a n y stage. A fixed p r o t e i n level f r o m 20 kg live w e i g h t t o slaughter m u s t be r a t h e r high to enable s l a u g h t e r pigs to p e r f o r m o p t i m a l l y . This is a p p a r e n t f r o m t h e e x p e r i m e n t s o f T h o m k e {1972) c o m p a r i n g 11.9, 13.4 a n d 17.5% c r u d e protein, a n d o f L a k s e s v e l a and Slagsvold ( 1 9 7 4 , 1 9 7 5 ) involving 14.8 a n d 15.8% c r u d e p r o t e i n f r o m a p p r o x i m a t e l y 20 t o 95 kg live weight, in w h i c h t h e TABLE V Consumption of the various feed mixtures and protein (kg/pig -- corrected as in Tables III and IV) Treatment VPC
VPCL
Experiment 1 Protein mixture Cereal mixture Total Crude protein (relative) Dig. crude protein
31.0 208.1 239.1 33.0 (100) 27.3
26.6 199.4 226.0 30.5 (92.4) 25.2
Experiment 2 Protein mixture Cereal mixture Total Crude protein (relative) Dig. crude protein
32.1 220.9 253.0 33.8 (100) 27.9
29.6 217.6 247.2 32.4 (95.8) 26.8
VPCM -----32.9 224.5 257.4 34.5 (102.1) 28.5
FPC --247.0 35.6 (107.9) 29.2 --263.8 38.0 (112.4) 31.3
626
15
cb
14
c
$
12
~/"
"--~,.
FPC
c
?
~ 10
121
B 20
I
I
30
40
~
5
I
I,
I
I
I
60
70
BO
90
100
Live weight (kg)
Fig. 1. Digestible c r u d e p r o t e i n in p e r c e n t a g e o f feed at t h e various stages o f live weight.
higher levels gave the best results. As well, more protein-rich diets performed best when the dietary protein level was reduced only one step, at 36--63 kg (Robinson et al., 1964), or was reduced at 50 kg live weight (Madsen, 1964; Hansen and Bresson, 1974). In addition to production traits, the latter authors presented data showing better returns with higher protein levels.
Compensatory growth Compensatory growth was not seen in the experiments recorded here. Figure 2 shows that a lead obtained on the adjusted diet over the first weeks was sustained up to slaughter, as in earlier experiments (Laksesvela and Slagsvold, 1974; 1975). This is at variance with the quoted results of Madsen (1964), FrSlich and Thomke (1969) and Robstad and SkrSvseth (1973). Differences in the growth rate of the pigs may offer an explanation. The pigs grew more slowly in the experiments of these authors than in those recorded here. For example, the pigs attained an average daily gain of 718 g on the best diet in the present experiments, as compared to 582 g in the experiments of Madsen (1964). His experiments were carried out about 11 years earlier, and the steady improvement of the genetic material may be the reason for differences in growth rate. In this context, it may be mentioned that Madsen and Mortensen (1975) concluded in later experiments that only one mixture from 20 to 90 kg is not the best. Modern, fast-growing pigs show hardly any lag in growth rate right up to slaughter. Within the short time they are reared, they have probably little
627
90 80
J
°o"
70 60
..£:
._1
j/~_ o°,°
50 40
/~ 30 20
ooo''w°
~
~ 14
~ o° °
,°°
°oOo°°
°°°°°°° I
I 28
42
56
I
I
I
70
84
98
Days on e x p e r i m e n t
Fig. 2. Live weight gain. Averages for the two tests.
chance of producing compensatory growth. If this is so, compensatory growth is becoming less important the better the growth of the pigs. Feed and protein saving Feed and protein saving may be most efficiently achieved when slaughter pigs are optimally fed all the time. Even when preceded by a deficiency, excesses later may be a waste. This assumption was supported by the experiments reported here, but was recently contradicted by results of Kirchgessner and Roth (1976), who obtained best results when young pigs were given very small quantities of total feed. It may seem puzzling that pigs receiving VPC required 11 days less than those on FPC to reach a live weight of 95 kg, while VPC saved only 8--10 kg feed per pig. Daily allowances of feed were adjusted weekly according to live weight, which meant that the fastest growing pigs received the greatest allowances of feed. It seems that the extra allowances were not utilized as efficiently as could probably be expected. Diet FPC contained a moderate total protein level of 14.4%. A higher protein level would presumably have stimulated growth, but the pigs receiving FPC would in that case have had a still higher over-consumption of protein as compared to those given VPC. Use of labour and revenue Rationalization at the expense of physiologically correct feeding must not go so far that it reduces revenue to zero in less fortunate cases. If so, the
628 e x t r a t r o u b l e involved in using t w o m i x t u r e s instead o f o n e m a y be the o n l y w o r k for which t h e p r o d u c e r gets paid.
Total lysine level T h e t o t a l lysine level o f VPC fell gradually f r o m 0.98 t o 0.65% d u r i n g the p e r i o d o f adding t h e p r o t e i n m i x t u r e to the cereal m i x t u r e , t h e latter a l o n e c o n t a i n i n g 0.39%. T h e U.S. N a t i o n a l R e s e a r c h Council ( 1 9 7 3 ) r e c o m m e n d 0.70% f o r pigs o f 2 0 - - 3 5 kg and 0.57% for finishing pigs. It a p p e a r s f r o m Fig. 2 t h a t s u p p l e m e n t a t i o n of the t e s t diet w i t h lysine a c t e d f a v o u r a b l y at an earlier stage t h a n w o u l d be e x p e c t e d in view o f t h e N a t i o n a l R e s e a r c h Council figures. A c c o r d i n g to British e x p e r i m e n t s , t h e lysine r e q u i r e m e n t s o f pigs are c o n s i d e r a b l y higher t h a n the figures q u o t e d a b o v e ( R o b i n s o n et al., 1964). In a 16% p r o t e i n diet, B a k e r et al. ( 1 9 7 5 ) in the U.S.A. o b t a i n e d b e t t e r results with 0.83 t h a n w i t h 0.75% lysine. ACKNOWLEDGEMENTS It is m u c h a p p r e c i a t e d t h a t P r o f e s s o r P. Slagsvold e n c o u r a g e d this research, and t h a t MSllesentralen A/S m i x e d t h e feed and lent facilities for o n e experim e n t at Arteid. F u r t h e r , t h a t P e l s d y r f o r s S k s g a r d e n , Heggedal, l e n t facilities for t h e o t h e r e x p e r i m e n t , and t h a t Mr. J. SvarttjSnnli and Mr. J. Nes t o o k care o f t h e animals. F e e d analyses were carried o u t b y S t a t e n s l a n d b r u k s k j e m i s k e k o n t r o l l s t a s j o n , Moss, a m i n o acid analyses b y N L V F ' s a m i n o s y r e l a b o r a t o r i u m A s - N L H , a n d available lysine b y the B i o t e k n i s k I n s t i t u t , Kolding. REFERENCES Baker, D.H., Katz, R.S. and Easter, R.A., 1975. Lysine requirement of growing pigs at two levels of dietary protein. J. Anim. Sci., 40: 851--856. Breirem, K., 1975. F6rnormer. In: K.K. Heje (Editor), Lommeh~ndbok for jordbrukere, skogbrukere, meierister og hagebrukere, 83 : 118--123. FrSlich, A. and Thomke, S., 1969. Om slaktsvinens proteinfSrsSrjning. LantbrukshSgskolans fSrsSksledarm5ten 1969, Uppsala. Konsulentavdelingens stencilserie, Husdjur, no. 9, pp. 7.1--7.35. Hansen, V. and Bresson, S., 1974. Nedsatte proteinnormer til slagterisvin. Ugeskr. Agron. Horton., 3(20): 400--402. Kirchgessner, M. and Roth, F.X., 1976. Zum Einfluss der Ern/ihrungsintensit/it von Ferkeln auf die spiitere Mast- und Schlachtleistung. Ziichtungskunde, 48: 45--55. Laksesvela, B. and Slagsvold, P., 1974. F6rtyper og lqlnnsomhet i slaktegrisproduksjon. Nor. Landbruk, 64(18): 18--20. Laksesvela, B. and Slagsvold, P., 1975. Mer protein til slaktesvin mens de er unge har gitt bedre vekst og stqtrre dekningsbidrag. Nor. Landbruk, 65(5): 18--19. Madsen, A., 1964. Faerdige foderblandinger til slagterisvin. LandSkonomisk ForsSgslaboratoriums efter£rsmSde, Arbog 1964, pp. 200--213. Madsen, A. and Mortensen, H.P., 1975. Protein og aminosyrer til slagterisvin. Ugeskr. Agron. Horton., 4(17): 325--326.
629
National Research Council, 1973. Nutrient Requirements of Swine. Washington D.C. No. 2, 30 pp. Robinson, D.W., Morgan, J.T. and Lewis, D., 1964. Protein and energy nutrition of the bacon pig. III. The effect of reducing the protein content of pig diets at different weights. J. Agric. Sci., Camb., 63: 409--414. Robstad, A.M. and SkrSvseth, O., 1973. Protein i svinef6ringa. Nor. Landbruk, 63(25/26): 5. Thomke, S., 1972. Uber den Futterwert yon Gerste fiir Mastschweine. Der Einfluss standortbedingter Proteingehaltsunterschiede. Z. Tierernaehr. Futtermittelk., 29: 132--165.
A D J U S T M E N T S O F T H E P R O T E I N L E V E L F O R S L A U G H T E R PIGS A N D S U P P L E M E N T A T I O N WITH LYSINE AND METHIONINE
B. LAKSESVELA Department of Animal Husbandry and Genetics, The Veterinary College of Norway, Oslo (Norway)
(Received January 15th, 1976)
ABSTRACT Laksesvela, B., 1976. Adjustments of the protein level for slaughter pigs and supplementation with lysine and methionine. Anita. Feed Sci. Technol., 1 : 619--629. In two replicate experiments, pigs were fed on a diet in which protein was progressively reduced as they grew from 20 to 70 kg, and thereafter on a cereal mixture alone (treatment VPC), or on a diet in which the protein content was the same from beginning to slaughter, at 95 kg live weight (treatment FPC). Diet VPC resulted in statistically faster growth and better feed efficiency than FPC. Diet VPC, with 0.12% lysine added to the cereal component (VPCL), significantly improved the growth rate in comparison to both VPC and FPC, and also feed efficiency as compared to FPC. Methionine added at a level of 0.1% instead of lysine (VPCM) did not produce any improvement. Carcass quality was not significantly affected by the various treatments. Compensatory growth was not visible on FPC, which was deficient in protein in the beginning and excessive later.
INTRODUCTION It is stated a l m o s t a x i o m a t i c a l l y t h a t y o u n g , fast-growing animals require a higher p r o t e i n level in their feed t h a n older animals. The same applies to minerals and vitamins, for w h i c h the r e q u i r e m e n t s are fairly well k n o w n . These s t a t e m e n t s are based o n n u m e r o u s e x p e r i m e n t s in various countries. It has, h o w e v e r , been argued r e c e n t l y t h a t adjusting the p r o t e i n level in the feed a c c o r d i n g t o live weight or age is n o w less i m p o r t a n t for slaughter pigs. One basis for this a r g u m e n t is t h a t m o d e r n pigs are capable o f d e p o s i t i n g p r o t e i n at a high rate over a m u c h wider range o f b o d y weight t h a n the older type. A n o t h e r a r g u m e n t is t h a t we can m a k e use o f so-called c o m p e n s a t o r y g r o w t h , m e a n i n g t h a t slaughter pigs can m a k e up later for deficiencies in the early p a r t o f the rearing period, p r o v i d e d t h a t t h e y get sufficient o f t h e deficient n u t r i e n t s later. The a b o v e e x p l a n a t i o n s were p u t f o r w a r d w h e n FrSlich and T h o m k e {1969} o b t a i n e d equally g o o d results with adjusted and u n a d j u s t e d p r o t e i n
620 (and vitamin and mineral) levels from 20 to 90 kg live weight. Compensatory growth was recorded, as was the case in earlier Danish experiments (Madsen, 1964). The same tendency appeared vaguely in a preliminary Norwegian test (Robstad and SkrSvseth, 1973). All these authors found that no adjustments were as good as frequent adjustments, under the conditions of their experiments. Contrarily, Laksesvela and Slagsvold (1974, 1975) registered significantly faster growth and better feed utilization in three replicated tests when adjusting protein, vitamin and mineral levels according to live weight as compared to no adjustments. Regulating the nutrient levels only once, from higher to lower levels at 60 kg live weight, gave intermediate results. Total consumption of protein was approximately the same on the three different regimens. Similar results have been found with gilts reared for breeding purposes (Laksesvela, unpublished). The system prescribing a fixed allowance of a high-protein mixture from start to slaughter does, however, not work satisfactorily today, because cereals often contain sufficient protein for pigs having reached a live weight of approximately 70 kg. After that stage protein concentrates should be expected to be superfluous. The present paper describes two replicate experiments in which a daily allowance of 0.35 kg high-protein mixture was withdrawn at a live weight of 70 kg. Thereafter, the pigs received only the basal feed, consisting of mixed cereals fortified with vitamins and minerals. Adjusting the protein level according to age provided the same total quantity of protein up to a live weight of approximately 80 kg as did only one mixture, but subsequently required less protein. Additions of lysine or methionine to the cereal mixture were also tried. EXPERIMENTAL Animals and housing Norwegian Landrace gilts and castrated males were reared on concrete floors in heated houses. Experiment 1 comprised three dietary treatments, each given to 7 group-fed pigs, and Experiment 2 four dietary treatments each given to 8 individually-fed pigs. The groups were as uniform as possible as to litter, sex and weight. The pigs were slaughtered at a live weight of approximately 95 kg. Dietary treatments and codes The treatment for which the protein content of the diet was varied according to the age of the pigs, by changing the proportions of protein mixture and cereal mixture, was called VPC. When lysine was added to its cereal mixture, the regimen was called VPCL, and with methionine added, VPCM. The treatment consisting of one diet, having a fixed ratio of protein concentrates to cereals, was designated FPC.
621
Composition of diets The constituents of diets VPC and FPC, and their nutrient content, are listed in Table I. All nutrients included in the table were determined by analysis, except for values of ME and digestible crude protein, which were calculated. The cereal mixture in VPCL was fortified with 0.12% L-lysine, and the cereal mixture in VPCM with 0.1% DL-methionine. Daily allowances of feed and the quantities they conveyed of certain nutrients at various live-weights are set out in Table II. Feed allowances were adjusted with an accuracy of 0.1 kg on the basis of weekly weighings. Daily feed rations were divided into two meals, after which water was offered according to appetite. RESULTS The various data from Experiments 1 and 2 are presented in Tables III and IV, respectively. In both experiments VPC was more favourable than FPC, and VPCL was better than VPC.
Daily weight gain Daily weight gain in the two experiments was, on the average, 670 g on VPC, 708 g on VPCL and 608 g on FPC. The smallest differences were significant at the 2--5% levels, the greatest at the 0.1% level. As all pigs were slaughtered at approximately 95 kg live weight, the faster gain reduced the rearing time. Pigs fed VPC required approximately 11 days less than those fed FPC, and those fed VPCL approximately 5 days less than on VPC.
Feed efficiency Feed consumed per unit gain (kg/kg) was on average 3.25 for VPC, 3.09 for VPCL and 3.39 for FPC. Statistical analyses could be carried out only for the individually-fed pigs in Experiment 2, VPC and VPCL being significantly better than FPC at respective levels of 5% and 1%. Supplementation with methionine did not produce any improvement.
Carcass quality Carcass quality was good, being equal on the various diets, according to all measures taken. In addition, the general health of the pigs was similar for all the different diets.
622
TABLEI C o m p o s i t i o n a n d n u t r i e n t c o n t e n t o f diets VPC a n d FPC ( p e r c e n t e x c e p t w h e r e o t h e r w i s e stated) Protein m i x t u r e in VPC Constituents B l o o d meal, s p r a y dried Fish m e a l M e a t a n d b o n e m e a l - - low fat Soya bean meal -- extracted Oats, g r o u n d Barley, g r o u n d Rye, ground Sorghum, ground W h e a t offals Molasses Dicalcium phosphate Salt Mineral m i x a Micro m i n e r a l s b Vitamin mix c Methionine Total Nutrient content M.E. ( M c a l / k g ) Crude protein Dig. c r u d e p r o t e i n Fat C r u d e fibre Ca P NaC1 Lysine Methionine + cystine Isoleucine Threonine Available lysine
Cereal m i x t u r e in VPC
FPC
3 10 17 28.6 28 ---11.6 --1 -0.38 0.3 0.12
----20 60 17.7 ---1.3 0.12 0.8 -0.08 --
1.5 2 2 3.3 21 35.5 15 10 4 3.4 1.83 0.3 -0.07 0.1 --
100.00
100.00
100.00
2.76 35.2 29.5 4.1 7.0 1.9 1.4 1.24 2.22 1.37 1.45 1.41 1.70
2.93 10.2 8.4 1.9 4.8 0.53 0.57 0.28 0.39 0.44 0.40 0.37 0.27
2.89 14.4 11.5 2.7 4.7 0.78 0.73 0.41 0.64 0.64 0.54 0.52 0.46
a C o m p o s i t i o n : CaCO3, 46%; CaHPO4 • 2 H 2 0 , FeSO4, 0.82%; Z n S O , , 0.43%; CuSO4 • 5 H 2 0 , b C o n t a i n i n g : Mg, 11.9%; Fe, 3.3%; Mn, 6.0%; 41.5% CaCO3 as a carrier. C C o m p o s i t i o n per g r a m : 3 0 0 0 I.U. vit.A; 4 3 0 0.007 mg cobalamin.
34%; salt, 1 6 . 2 4 % ; MgO, 2%; M n O , 0.3%; 0.19%; CoSO4, 0 . 0 1 2 % ; KI, 0.01%. Zn, 3.9%, Cu, 1.1%; Co, 0 . 0 8 7 % ; I, 0 . 1 5 5 % ; I.U. vit.D; 20 m g vit.E; 3 m g r i b o f l a v i n ; a n d
623
O~
~ m
O~
C~
O,1
oO
o ~m
v
oO oO
0
I
I~
~
~
~=~
=
e~ ~
o~ ~ ° ~
.< Z
624
T A B L E III E x p e r i m e n t 1. G r o w t h rate, feed e f f i c i e n c y and carcass quality. Values c o r r e c t e d to 95 kg live weight and a dressing-out p e r c e n t a g e o f 70 (+ S.E.) Treatments
No. days f r o m 21.2 t o 95 kg Daily gain (g) Kg f e e d / k g gain Kcal M E / k g gain Back fat t h i c k n e s s ( m m ) Shoulder Midback Loin Side fat t h i c k n e s s ( m m ) Area o f m e a t c u t l e t ( c m 2) Fat firmness p o i n t s 0--15 Fat c o l o u r p o i n t s 0--15 Meat c o l o u r p o i n t s 0--5
VPC
VPCL
FPC
113.4 (±4.9) 653 (+46) 3.24 9.35
107.1 (±5.1) 697 (+42) 3.03 8.80
122.4 (-+6.3) 606 (-+39) 3.34 9.68
33.8 16.8 25.8 18.5 29.8
(+-2.3) (-+1.4) (-+2.2) (± 1.9) (+ 3.2)
31.6 17.1 27.1 18.8 30.2
(+2.0) (-+1.5) (-+2.3) (-+ 2.0) (± 2.9)
31.2 17.2 28.3 19.7 31.4
(_+2.1) (+ 1.8) (-+2.3) (-+ 2.2) (±3.3)
12.0 (± 1.0)
11.7 (+1.1)
11.9 (+1.3)
12.8 (-+0.9)
12.4 (-+1.3)
12.6 (-+1.2)
3.7 (±0.5)
3.6 (+0.4)
3.5 (+0.5)
T A B L E IV Experiment 2. Growth rate, feed efficiency and carcass quality. Values corrected to 95 kg live weight and a dressing-out percentage of 70 (+S.E.) Treatment
No. days from 17.7 to 95 kg Daily gain (g) Kg feed/kg gain Kcal ME/kg gain Back fat thickness (ram) Shoulder Midback Loin Side fat thickness (ram) Area of meat cutlet (cm 2) Fat firmness points 0--15 Fat colour points 0--15 Meat colour points 0--5
VPC
VPCL
VPCM
FPC
113.5 (-+4.8) 684 (+-38) 3.26 (-+0.18) 9.48 (+0.36)
109.5 (+3.9) 718 (±43) 3.15 (+-0.14) 9.15 (-+0.32)
116.1 (+-4.6) 666 {+48) 3.33 (+0.21) 9.68 (+-0.44)
126.3 (+-5.2) 609 (+-34) 3.43 (±0.13) 9.93 (-*0.31)
34.3 18.7 22.4 19.6 30.1
(± 2.1) (-+1.4) (+2.0) (+-1.7) (-+2.7)
34.2 17.7 22.6 21.5 32.2
(+-1.9) (±1.1) (-+2.2) (÷1.5) (±2.9)
32.1 16.9 19.6 20.5 30.3
(+-2.2) (+1.2) (-+1.8) (+1.8) (+-2.6)
34.3 17.4 21.4 20.7 30.0
(± 2.3) (+-1.3) (-+1.9) (+1.7) (+-3.1)
11.6 (+ 0.9)
11.8 (+-1.0)
11.7 (± 1.1)
11.4 (+-1.3 )
11.1 (+-0.%
12.1 (-+1.1)
11.1 (+1.2)
11.5 (± 1.0)
3.0 (-+0.4)
3.0 (+-0.3)
3.3 (+-0.5)
2.9 (±0.4)
625
Expenditure of protein T h e use o f VPC saved a p p r o x i m a t e l y 10, a n d V P C L 16% p r o t e i n as c o m p a r e d to FPC, while V P C L saved 6% in c o m p a r i s o n to VPC, c a l c u l a t e d as g o f d i e t a r y p r o t e i n p e r kg carcass p r o d u c e d . This saving t o o k place a f t e r the pigs h a d a t t a i n e d a live w e i g h t o f nearly 80 kg. T h e t o t a l i n t a k e s o f the various feed m i x t u r e s and o f p r o t e i n are set o u t in T a b l e V. CONCLUSIONS
Protein levels T a b l e II and Figure 1 s h o w t h a t VPC and FPC d i f f e r e d greatly as t o s u p p l y o f p r o t e i n , b o t h in t h e b e g i n n i n g a n d end o f the rearing period. When c o m paring t h e supplies o f digestible c r u d e p r o t e i n t o the r e q u i r e m e n t s s t a t e d b y B r e i r e m ( 1 9 7 5 ) it a p p e a r s t h a t VPC was s a t i s f a c t o r y , while FPC was d e f i c i e n t in t h e beginning, b u t c h a n g e d gradually to b e c o m e v e r y excessive later. Ca, P and NaC1 a n d v i t a m i n s varied also, b u t were n o t s u p p o s e d t o be d e f i c i e n t at a n y stage. A fixed p r o t e i n level f r o m 20 kg live w e i g h t t o slaughter m u s t be r a t h e r high to enable s l a u g h t e r pigs to p e r f o r m o p t i m a l l y . This is a p p a r e n t f r o m t h e e x p e r i m e n t s o f T h o m k e {1972) c o m p a r i n g 11.9, 13.4 a n d 17.5% c r u d e protein, a n d o f L a k s e s v e l a and Slagsvold ( 1 9 7 4 , 1 9 7 5 ) involving 14.8 a n d 15.8% c r u d e p r o t e i n f r o m a p p r o x i m a t e l y 20 t o 95 kg live weight, in w h i c h t h e TABLE V Consumption of the various feed mixtures and protein (kg/pig -- corrected as in Tables III and IV) Treatment VPC
VPCL
Experiment 1 Protein mixture Cereal mixture Total Crude protein (relative) Dig. crude protein
31.0 208.1 239.1 33.0 (100) 27.3
26.6 199.4 226.0 30.5 (92.4) 25.2
Experiment 2 Protein mixture Cereal mixture Total Crude protein (relative) Dig. crude protein
32.1 220.9 253.0 33.8 (100) 27.9
29.6 217.6 247.2 32.4 (95.8) 26.8
VPCM -----32.9 224.5 257.4 34.5 (102.1) 28.5
FPC --247.0 35.6 (107.9) 29.2 --263.8 38.0 (112.4) 31.3
626
15
cb
14
c
$
12
~/"
"--~,.
FPC
c
?
~ 10
121
B 20
I
I
30
40
~
5
I
I,
I
I
I
60
70
BO
90
100
Live weight (kg)
Fig. 1. Digestible c r u d e p r o t e i n in p e r c e n t a g e o f feed at t h e various stages o f live weight.
higher levels gave the best results. As well, more protein-rich diets performed best when the dietary protein level was reduced only one step, at 36--63 kg (Robinson et al., 1964), or was reduced at 50 kg live weight (Madsen, 1964; Hansen and Bresson, 1974). In addition to production traits, the latter authors presented data showing better returns with higher protein levels.
Compensatory growth Compensatory growth was not seen in the experiments recorded here. Figure 2 shows that a lead obtained on the adjusted diet over the first weeks was sustained up to slaughter, as in earlier experiments (Laksesvela and Slagsvold, 1974; 1975). This is at variance with the quoted results of Madsen (1964), FrSlich and Thomke (1969) and Robstad and SkrSvseth (1973). Differences in the growth rate of the pigs may offer an explanation. The pigs grew more slowly in the experiments of these authors than in those recorded here. For example, the pigs attained an average daily gain of 718 g on the best diet in the present experiments, as compared to 582 g in the experiments of Madsen (1964). His experiments were carried out about 11 years earlier, and the steady improvement of the genetic material may be the reason for differences in growth rate. In this context, it may be mentioned that Madsen and Mortensen (1975) concluded in later experiments that only one mixture from 20 to 90 kg is not the best. Modern, fast-growing pigs show hardly any lag in growth rate right up to slaughter. Within the short time they are reared, they have probably little
627
90 80
J
°o"
70 60
..£:
._1
j/~_ o°,°
50 40
/~ 30 20
ooo''w°
~
~ 14
~ o° °
,°°
°oOo°°
°°°°°°° I
I 28
42
56
I
I
I
70
84
98
Days on e x p e r i m e n t
Fig. 2. Live weight gain. Averages for the two tests.
chance of producing compensatory growth. If this is so, compensatory growth is becoming less important the better the growth of the pigs. Feed and protein saving Feed and protein saving may be most efficiently achieved when slaughter pigs are optimally fed all the time. Even when preceded by a deficiency, excesses later may be a waste. This assumption was supported by the experiments reported here, but was recently contradicted by results of Kirchgessner and Roth (1976), who obtained best results when young pigs were given very small quantities of total feed. It may seem puzzling that pigs receiving VPC required 11 days less than those on FPC to reach a live weight of 95 kg, while VPC saved only 8--10 kg feed per pig. Daily allowances of feed were adjusted weekly according to live weight, which meant that the fastest growing pigs received the greatest allowances of feed. It seems that the extra allowances were not utilized as efficiently as could probably be expected. Diet FPC contained a moderate total protein level of 14.4%. A higher protein level would presumably have stimulated growth, but the pigs receiving FPC would in that case have had a still higher over-consumption of protein as compared to those given VPC. Use of labour and revenue Rationalization at the expense of physiologically correct feeding must not go so far that it reduces revenue to zero in less fortunate cases. If so, the
628 e x t r a t r o u b l e involved in using t w o m i x t u r e s instead o f o n e m a y be the o n l y w o r k for which t h e p r o d u c e r gets paid.
Total lysine level T h e t o t a l lysine level o f VPC fell gradually f r o m 0.98 t o 0.65% d u r i n g the p e r i o d o f adding t h e p r o t e i n m i x t u r e to the cereal m i x t u r e , t h e latter a l o n e c o n t a i n i n g 0.39%. T h e U.S. N a t i o n a l R e s e a r c h Council ( 1 9 7 3 ) r e c o m m e n d 0.70% f o r pigs o f 2 0 - - 3 5 kg and 0.57% for finishing pigs. It a p p e a r s f r o m Fig. 2 t h a t s u p p l e m e n t a t i o n of the t e s t diet w i t h lysine a c t e d f a v o u r a b l y at an earlier stage t h a n w o u l d be e x p e c t e d in view o f t h e N a t i o n a l R e s e a r c h Council figures. A c c o r d i n g to British e x p e r i m e n t s , t h e lysine r e q u i r e m e n t s o f pigs are c o n s i d e r a b l y higher t h a n the figures q u o t e d a b o v e ( R o b i n s o n et al., 1964). In a 16% p r o t e i n diet, B a k e r et al. ( 1 9 7 5 ) in the U.S.A. o b t a i n e d b e t t e r results with 0.83 t h a n w i t h 0.75% lysine. ACKNOWLEDGEMENTS It is m u c h a p p r e c i a t e d t h a t P r o f e s s o r P. Slagsvold e n c o u r a g e d this research, and t h a t MSllesentralen A/S m i x e d t h e feed and lent facilities for o n e experim e n t at Arteid. F u r t h e r , t h a t P e l s d y r f o r s S k s g a r d e n , Heggedal, l e n t facilities for t h e o t h e r e x p e r i m e n t , and t h a t Mr. J. SvarttjSnnli and Mr. J. Nes t o o k care o f t h e animals. F e e d analyses were carried o u t b y S t a t e n s l a n d b r u k s k j e m i s k e k o n t r o l l s t a s j o n , Moss, a m i n o acid analyses b y N L V F ' s a m i n o s y r e l a b o r a t o r i u m A s - N L H , a n d available lysine b y the B i o t e k n i s k I n s t i t u t , Kolding. REFERENCES Baker, D.H., Katz, R.S. and Easter, R.A., 1975. Lysine requirement of growing pigs at two levels of dietary protein. J. Anim. Sci., 40: 851--856. Breirem, K., 1975. F6rnormer. In: K.K. Heje (Editor), Lommeh~ndbok for jordbrukere, skogbrukere, meierister og hagebrukere, 83 : 118--123. FrSlich, A. and Thomke, S., 1969. Om slaktsvinens proteinfSrsSrjning. LantbrukshSgskolans fSrsSksledarm5ten 1969, Uppsala. Konsulentavdelingens stencilserie, Husdjur, no. 9, pp. 7.1--7.35. Hansen, V. and Bresson, S., 1974. Nedsatte proteinnormer til slagterisvin. Ugeskr. Agron. Horton., 3(20): 400--402. Kirchgessner, M. and Roth, F.X., 1976. Zum Einfluss der Ern/ihrungsintensit/it von Ferkeln auf die spiitere Mast- und Schlachtleistung. Ziichtungskunde, 48: 45--55. Laksesvela, B. and Slagsvold, P., 1974. F6rtyper og lqlnnsomhet i slaktegrisproduksjon. Nor. Landbruk, 64(18): 18--20. Laksesvela, B. and Slagsvold, P., 1975. Mer protein til slaktesvin mens de er unge har gitt bedre vekst og stqtrre dekningsbidrag. Nor. Landbruk, 65(5): 18--19. Madsen, A., 1964. Faerdige foderblandinger til slagterisvin. LandSkonomisk ForsSgslaboratoriums efter£rsmSde, Arbog 1964, pp. 200--213. Madsen, A. and Mortensen, H.P., 1975. Protein og aminosyrer til slagterisvin. Ugeskr. Agron. Horton., 4(17): 325--326.
629
National Research Council, 1973. Nutrient Requirements of Swine. Washington D.C. No. 2, 30 pp. Robinson, D.W., Morgan, J.T. and Lewis, D., 1964. Protein and energy nutrition of the bacon pig. III. The effect of reducing the protein content of pig diets at different weights. J. Agric. Sci., Camb., 63: 409--414. Robstad, A.M. and SkrSvseth, O., 1973. Protein i svinef6ringa. Nor. Landbruk, 63(25/26): 5. Thomke, S., 1972. Uber den Futterwert yon Gerste fiir Mastschweine. Der Einfluss standortbedingter Proteingehaltsunterschiede. Z. Tierernaehr. Futtermittelk., 29: 132--165.