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Animal Feed Science and Technology, 3 (1978) 191--200 191 © Elsevier Scientific Publishing Company, Amsterdam -- Printed in The Netherlands
BLOOD MEAL AS A SOURCE OF PROTEIN FOR GROWER/FINISHER PIGS
R.H. KING and R.G. CAMPBELL Department o f Agriculture, Animal Research Institute, Werribee, Victoria, 3030 (Australia) (Received 15 November 1977)
ABSTRACT King, R~I. and Campbell, R.G., 1978. Blood meal as a source of protein for grower/finisher pigs. Anita. Feed Sci. Technol., 3: 191--200. In the first of four experiments five dietary levels of ring-dried blood meal (0, 3.0, 5.9, 8.9 and 11.8%) were used for pigs of 21--70 kg live weight at two levels of feeding (restricted and ad libitum). Pigs receiving either 5.9 or 8.9% blood meal grew more efficiently than pigs receiving either 0 or 11.8%. The feed conversion ratio of pigs given 3.0% blood meal was of intermediate value. There were significant interactions; when feeding was ad libitum, a reduced intake at the higher levels of blood meal resulted in a slower growth rate at the 11.8% level of blood meal, but with restricted feeding, up to 11.8% blood meal could be included without adverse effects on feed intake or growth rate. In the second and third experiments grower pigs fed ad libitum, between 22 and 50 kg live weight, were used to investigate the effects of the addition of a feed flavour or of isoleucine to a diet containing 12% blood meal. Experiment 2 involved two levels of blood meal (0 and 12%) and two levels of a feed flavour (0 and 50 p.p.m.). The feed flavour failed to prevent the reduction in feed intake and growth caused by 12% blood meal. In the third experiment the addition of 0.1% isoleucine to the 12% blood meal diet significantly increased both intake and growth rate but not to the level of a diet containing no blood meal. In Experiment 4 the digestible energy (+ SE) content of blood meal was determined to be 20.8 (-~. 2.15) MJ/kg dry matter. INTRODUCTION B l o o d m e a l is s i m p l y g r o u n d d r i e d b l o o d a n d is a r i c h s o u r c e o f p r o t e i n a n d m o s t a m i n o acids, p a r t i c u l a r l y l y s i n e . A l t h o u g h b l o o d m e a l has b e e n w i d e l y u s e d as a p r o t e i n s o u r c e f o r pigs, it has g e n e r a l l y b e e n r e c o m m e n d e d t h a t i t s h o u l d b e l i m i t e d t o a b o u t 3% i n pig d i e t s t o a v o i d p r o b l e m s o f p o o r palatability (Gutteridge and Trapnell, 1972). I n t h e p a s t , b l o o d m e a l has b e e n d r i e d b y c o n v e n t i o n a l v a t - d r y i n g p r o c e dures, resulting in a p r o d u c t of p o o r p a l a t a b i l i t y and with a low availability o f l y s i n e . H o w e v e r , n e w e r flash d r y i n g p r o c e d u r e s , i n c l u d i n g b o t h t h e ringdrying process and the rotary s t e a m - d r y i n g process, have i m p r o v e d b o t h the p a l a t a b i l i t y a n d l y s i n e b i o a v a i l a b i l i t y o f b l o o d m e a l (Miller, 1 9 7 7 ) . R e c e n t e x p e r i m e n t s h a v e s h o w n t h a t levels m u c h h i g h e r t h a n t h e p r e v i o u s l y r e c o m -
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mended level of 3% can be used for pigs without deleterious effects on feed intake or growth performance (Rerat et al., 1975), although Wahlstrom and Libal (1977) found that 8% blood meal significantly reduced the feed intake and growth rate of grower pigs. Becker et al. (1963) reported that pigs given a 15% blood meal diet grew satisfactorily provided that the isoleucine content of the diet was adequate. Blood meal contains a high level of leucine and there is some evidence that a high level of dietary leucine may elevate the isoleucine requirement (Taylor et al., 1977b). This paper reports four experiments to compare the performance of pigs given various amounts of blood meal and to determine the extent to which palatability and the level of leucine may limit the level of inclusion of blood meal in pig diets. In Experiment 1 the performance of grower/finisher pigs was used to compare diets with increasing levels of blood meal. The aims of Experiments 2 and 3 were to investigate the effect of adding a feed flavour or isoleucine to high blood meal diets. The digestible energy (DE} c o n t e n t of blood meal was determined in the fourth experiment. MATERIALS AND METHODS Animals
All the pigs were entire males selected from a minimal disease herd; they were Large White X (Large White X Berkshire). At 8 weeks of age and about 18 kg live weight the pigs were allocated to individual pens, 1.8 m X 0.7 m, in a fully enclosed but unheated piggery. In Experiment 1, experimental diets were given and observations began when individual pigs reached 21 kg live weight {mean 20.9 + 0.1 kg). In Experiments 2 and 3, experimental diets were given and observations began when individual pigs reached 22 kg live weight (means 22.2 -+ 0.2 kg and 22.1 + 0.2 kg, respectively). Design and treatments
Experiments 1 and 2 were factorial experiments. Sixty pigs were stratified according to live weight into six blocks o f ten pigs in Experiment 1. The experiment involved five levels of blood meal (0, 3.0, 5.9, 8.9 and 11.8%) and two levels of feeding (ad libitum and restricted}. In Experiment 2, 24 pigs were stratified according to live weight into six blocks of four pigs. The factors were blood meal (0 and 12.0%} and a feed flavour (0 and 50 p.p.m.). In each experiment the treatments were arranged in a randomized block design and each treatment had six replicates. Experiment 3 was of randomized block design with six pigs on each of three treatments, these being 0 and 12% blood meal and 12% blood meal supplemented with isoleucine. Diets
The diets (Table I) were formulated to be isonitrogenous and isocaloric
19.7 14.3 ± 0.09 0.90 0.81 0.71 1.30 0.93
Analysis Crude protein 3 D i g e s t i b l e e n e r g y +- S E ( M J / k g ) 4 Lysine 5 Available lysine 5 Isoleucine 5 Leucine s Valine s 19.8 1 5 . 2 -+ 0 . 1 1 0.97 0.88 0.64 1.41 1.03
3.0 77.25 9.0 7.5 2.2 0.3 --0.5 0.25
2
19.5 1 5 . 2 -+ 0 . 1 4 1.04 0.94 0.57 1.51 1.11
5.9 77.25 6.0 5.0 2.4 1.2 1.0 0.5 0.5 0.25
3
19.7 15.0 ± 0.07 1.11 1.01 0.50 1.63 1.20
8.9 77.25 3.0 2.5 3.5 1.9 1.5 0.5 0.5 0.25
4
19.4 14.9 + 0.07 1.17 1.08 0.44 1.73 1.28
11.8 77.25 --4.7 2.5 2.0 1.0 0.5 0.25
5
18.7 15.1 ± 0.17 0.90 0.81 0.71 1.30 0.93
-77.25 12.0 10.0 ----0.5 0.25
6
19.0 1 4 . 6 +~ 0 . 1 4 1.19 1.09 0.44 1.75 1.30
12.0 77.25 --7.0 -2.0 1.0 0.5 0.25
8
J Blood meal was dried by the ring-drying process. 2 T h e p r e m i x p r o v i d e d t h e f o l l o w i n g n u t r i e n t s ( p e r k g air d r y d i e t ) : v i t a m i n s ; A 3 8 3 0 i.u., D 3 3 3 0 i.u., E 3 3 i.u., K 6 6 0 p g , r i b o f l a v i n 3 . 3 m g , n i a c i n 1 6 . 5 m g , p a n t o t h e n i c a c i d 5 . 5 m g , p y r i d o x i n e 1.1 m g , B12 17 p g , b i o t i n 5 6 p g , c h o l i n e 1 1 0 0 rag; m i n e r a l s ; F e 8 8 m g , Z n 55 rag, M n 22 m g , C u 6 . 6 m g , Co 0 . 6 6 m g , I 0 . 2 2 rag, Se 0 . 1 1 rag. 3 Estimated for each diet by laboratory analyses. 4 D e t e r m i n e d in t h e d i g e s t i b i l i t y s t u d y w h e r e D E = g r o s s e n e r g y × d r y m a t t e r d i g e s t i b i l i t y ( B a t t e r h a m a n d M a n s o n , 1 9 7 0 ) . s Calculated for each diet from the analyses of ingredients.
-77.25 12.0 10.0 ----0.5 0.25
1
Diet
1, 2 a n d 3 (air d r y b a s i s )
Constituent Blood meal 1 Wheat Soya bean meal Meat and bone meal Starch Tallow Boneflour Limestone Mineral/vitamin premix 2 Salt
C o m p o s i t i o n o f d i e t s u s e d in E x p e r i m e n t s
TABLE I
~D
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in each ex p er imen t with an equal p r o p o r t i o n of wheat in each diet. Diets 7 and 9 were similar in composition to Diets 6 and 8, respectively, except that 50 p.p.m, o f feed flavour (Firanor No. 3, Firmenich et Cie, Geneva) was included. Diet 10 was similar in composition to Diet 8 except that 0.1% synthetic isoleucine was added. Diets 1--5 were used in E x p e r i m e n t 1, Diets 6--9 in E x p e r i m e n t 2 and Diets 6, 8 and 10 in Experiment 3.
Feeding and management Pigs were weighed weekly and the daily feed intake of those fed on a restricted basis was subsequently adjusted. Intakes were increased according to live weight f r o m 1.0 to 2.3 kg meal daily as live weight increased from 20 to 63 kg. All pigs in Experiments 2 and 3 were fed ad libitum and the feed intake of all pigs offered diets ad libitum was recorded weekly. Pigs in E x p e r i m e n t 1 were slaughtered at 70 kg live weight (mean 69.6 -+ 0.2 kg) and pigs in Experiments 2 and 3 were slaughtered at 50 kg live weight (means 51.1 + 0.2 kg and 51.2 + 0.4 kg, respectively). A b o u t 24 hours after slaughter the depth of backfat of each carcass was measured with an optical probe at 6.5 cm from the midline at the level of the last rib. The left ham was removed from each carcass by a cut at right angles to the b o d y and passing through the e x t r e m e anterior section of the femur. The p r o p o r t i o n of lean meat, fat and bone was determined by dissection.
Digestibility trials In each of two trials, ten entire males were confined to metabolism cages in a r o o m kept at about 20°C. The pigs were allowed ten days to become accustomed to the cages, after which t he y were weighed. In the first trial, two pigs were r a n d o m l y allotted to each of Diets 1--5 (Table I) for a 14-day period. At the end of this period the pigs were weighed and random l y re-allotted to the diets for a second 14-day period. In the second trial, the 10 pigs were given either Diet 6 or 8 to obtain estimates of the DE c o n t e n t of these diets. The average initial live weights of the pigs were 21.0 + 1.9 kg and 40.7 -+ 1.4 kg in Trials 1 and 2, respectively. Dry meal equivalent to 3.5% of the initial live weight in each test period was given to each pig daily, water (2/1, 2/1, w/w) being mixed with the meal. The faeces from each pig were collected daily on the last five days of each test period and stored at 1°C. At the end of each collection period, the combined daily faeces from each pig were weighed, thoroughly mixed and sampled for further analysis. Also in E x p e r i m e n t 4, eight estimates of the DE c o n t e n t of blood meal were obtained. Eight pigs, weighing initially 30.9 + 1.5 kg, were given either a basal diet of wheat or a test diet in which 10% of the basal diet was replaced by blood meal in an 8 X 2 factorial experiment. The basal diet contained 96.2% wheat, 2.0% steamed boneflour, 1.0% ground limestone, 0.5%
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m i n e r a l a n d v i t a m i n p r e m i x a n d 0.3% salt. M a n a g e m e n t a n d c o l l e c t i o n proc e d u r e s were similar to t h o s e d e s c r i b e d a b o v e a n d the D E c o n t e n t o f b l o o d m e a l was c a l c u l a t e d b y difference.
Chemical analyses T h e gross e n e r g y of all diets and freeze dried faeces s a m p l e s c o l l e c t e d in E x p e r i m e n t 4 was d e t e r m i n e d in an a d i a b a t i c b o m b c a l o r i m e t e r . P r o x i m a t e analysis o f diets and feeds was m a d e b y s t a n d a r d p r o c e d u r e s ( A s s o c i a t i o n o f Official A n a l y t i c a l Chemists, 1975). T h e a m i n o acid c o m p o s i t i o n a n d Silcock available lysine c o n t e n t s o f t h e feeds w e r e d e t e r m i n e d b y m e t h o d s d e s c r i b e d b y F o x (1971).
Statistical analysis G r o w t h p e r f o r m a n c e , dally feed i n t a k e and carcass q u a l i t y d a t a were subj e c t e d to s t a n d a r d analysis o f v a r i a n c e p r o c e d u r e , and significant d i f f e r e n c e s were e x a m i n e d b y D u n c a n ' s m u l t i p l e r a n g e t e s t ( D u n c a n , 1955). RESULTS T h e c r u d e p r o t e i n , essential a m i n o acid and available lysine c o n t e n t o f b l o o d m e a l are r e p o r t e d in T a b l e II.
TABLE II Crude protein and essential amino acid analyses of blood meal (air dry basis) Constituent
Percentage of feed
Percentage of crude protein
Crude protein Arginine Cystine Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Tyrosine Valine Available lysine
88.5 3.58 1.23 4.77 1.15 10.26 7.64 1.30 5.91 4.57 1.90 2.59 7.74 7.15
4.05 1.39 5.39 1.30 11.59 8.63 1.47 6.68 5.16 2.15 2.93 8.75 8.08
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Experiment 1 Pigs r e c e i v i n g e i t h e r 5 . 9 o r 8 . 9 % b l o o d m e a l g r e w pigs given either the highest or lowest level of blood feed conversion ratio of pigs given 3.0% blood meal meal had no effect on any of the carcass parameters had more backfat.
TABLE
more efficiently than meal (Table III). The was intermediate. Blood but pigs fed ad libitum
III
Experiment 1. Main effects of blood meal level and feeding level on growth performance and carcass characteristics of grower/finisher pigs (21--70 kg live weight)
Main effect
Feed conversion ratio
Backfat thickness (mm)
Lean meat in ham (%)
Blood meal level (%) 0 3.0 5.9 8.9 11.8
2.87 cd~ 2.79 bc 2.64 a 2.73 ab 2.91 d
19.2 20.2 19.6 18.4 19.2
66.3 65.3 66.3 65.5 64.2
Feeding level Ad libitum Restricted
2.94 b 2.64 a
21.1 b 17.6 a
65.5 65.5
Coefficient of variation (%)
4.8
15.6
3.1
1 In this and subsequent tables, within columns, for each main effect, means with different superscript letters are significantly different at the 5% level of probability (Duncan, 1955); in the absence of superscripts means are not significantly different.
T h e r e w e r e s i g n i f i c a n t i n t e r a c t i o n s b e t w e e n f e e d i n g level a n d b l o o d m e a l level ( T a b l e I V ) ; a r e d u c t i o n in f e e d i n t a k e a t t h e h i g h e r l e v e l s o f b l o o d m e a l retarded growth rate at the 11.8% blood meal level when feeding was ad libitum but not when it was restricted.
Experiment 2 Pigs g i v e n d i e t s w i t h o u t b l o o d m e a l a t e m o r e , g r e w f a s t e r a n d t e n d e d t o h a v e a b e t t e r f e e d c o n v e r s i o n r a t i o t h a n p i g s g i v e n 1 2 % b l o o d m e a l ( T a b l e V). The feed flavour had no effect on the intake, growth performance or carcass c h a r a c t e r i s t i c s o f t h e pigs.
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TABLE IV Experiment 1. Feed intake and growth rate of pigs grown from 21 to 70 kg live weight as influenced by blood meal level and feeding level Blood meal level (%)
Feed intake (kg/day) /kt libitum Restricted Growth rate (g/day) Ad libitum Restricted
0
3.0
5.9
8.9
11.8
2.30
2.27
2.21
2.13
1.99
1.64
1.64
1.64
1.65
1.62
760
774
796
756
641
606
623
655
628
598
L.S.D.
(P = 0.05)
Between any two means
Between any two differences
0.12
0.17
54
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TABLE V Experiment 2. Main effects of a feed flavour on growth performance and carcass characteristics of grower pigs (22--50 kg live weight) Main effect
Blood meal level (%) 0 12
Growth rate (g/day)
Feed conversion ratio
Feed intake (kg/day)
Backfat thickness (ram)
Lean meat in ham (%)
776 a 600 b
2.87 3.01
2.23 a 1.80 b
16.8 15.0
63.6 64.4
2.93 2.95
1.99 2.05
15.8 16.0
64.2 63.8
5.8
6.5
14.5
2.3
Feed flavour level (ppm) 0 680 50 695 Coefficient of variation (%)
6.0
Experiment 3 A s u m m a r y o f t h e r e s u l t s is g i v e n in T a b l e V I . T h e a d d i t i o n o f 0 . 1 % isoleucine to the 12% blood meal diet increased both feed intake and growth rate but not to the level of the diet containing no blood meal. Feed convers i o n r a t i o a n d c a r c a s s c h a r a c t e r i s t i c s w e r e n o t a f f e c t e d b y t h e t r e a t m e n t s alt h o u g h pigs g i v e n 1 2 % b l o o d m e a l t e n d e d t o h a v e a p o o r e r f e e d c o n v e r s i o n r a t i o a n d less b a c k f a t .
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TABLE VI Experiment 3. Effects of isoleucine supplementation of a high blood meal diet on growth performance and carcass characteristics of grower pigs (22--50 kg live weight) Treatment
0% blood meal 12% blood meal 12% blood meal + 0.1% isoleucine Coefficient of variation (%)
Growth rate (g/day)
Feed conversion ratio
Feed intake (kg/day)
Backfat thickness (mm)
Lean meat in ham (%)
782 a 579 c
2.87 3.00
2.24 a 1.73 c
17.6 13.9
63.3 64.9
687 b
2.88
1.97 b
16.9
64.5
4.9
7.6
7.9
15.3
2.7
Experiment 4 The digestible energy c o n t e n t s of Diets 1--8 are i n c l u d e d in Table I. The gross energy c o n t e n t o f b l o o d meal was 24.7 M J / k g d r y m a t t e r and the average DE c o n t e n t s (+ SE) o f b l o o d meal and the basal w h e a t diet were 20.8 (-+ 2.15) and 16.0 (_+ 0.18) M J / k g d r y m a t t e r , respectively. DISCUSSION The results o f the first e x p e r i m e n t indicate t h a t r e p l a c e m e n t of m o r e t h a n 75% o f s o y a bean meal and m e a t and b o n e meal with b l o o d meal decreased feed intake and g r o w t h rate w h e n pigs were fed ad l i b i t u m (Table IV). However, feed intake and g r o w t h rate were n o t adversely a f f e c t e d b y b l o o d meal w h e n pigs were fed o n a restricted basis. T h e DE c o n t e n t o f Diet 1 was l o w e r t h a n t h a t o f Diets 2--5 and the a p p a r e n t l y inferior feed c o n v e r s i o n ratio of Diet 1 was o n l y a reflection o f the l o w e r DE c o n t e n t o f this diet. T h e high lysine c o n t e n t (1.17%) of the diet c o n t a i n i n g 11.8% b l o o d meal in Experim e n t 1 m a y have c o n t r i b u t e d t o the p o o r e r feed c o n v e r s i o n ratio o f pigs given this diet. The feed c o n v e r s i o n e f f i c i e n c y o f pigs o f a similar live-weight range was r e d u c e d w h e n d i e t a r y lysine was raised f r o m 1.02% to 1.2% (R.G. Campbell, personal c o m m u n i c a t i o n ) . Wahlstrom and Libal ( 1 9 7 7 ) f o u n d t h a t m o r e t h a n 6% steam-dried b l o o d meal r e d u c e d the feed intake and g r o w t h rate o f g r o w e r pigs fed ad libitum. However, in o u r first e x p e r i m e n t , w h e n feeding was ad libitum, 8.9% b l o o d meal had n o adverse effects on g r o w t h rate or feed c o n v e r s i o n e f f i c i e n c y alt h o u g h feed intake was depressed. O u r observations w h e n feeding was restricted agree with t h o s e of R e r a t et al. ( 1 9 7 5 ) w h o fed b a r r o w s and gilts on a restricted basis b e t w e e n 25 and 60 kg live weight. T h e r e was little difference in the g r o w t h p e r f o r m a n c e o f b a r r o w s given 0 or 12% b l o o d meal, b u t gilts t e n d e d to eat less and grow slower w h e n given the 12% b l o o d meal diet.
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Feed f a v o u r s have been used with varying success to increase the feed consumption and growth rate of pigs, particularly young pigs (Hines, 1972). However, the addition of a feed flavour did n o t overcome the reduced voluntary feed intake o f pigs receiving a diet containing 12% blood meal, nor did it increase the feed c o n s u m p t i o n of pigs given diets w i t hout blood meal. The results of the third e x p e r i m e n t indicate an isoleucine deficiency in the diet containing 12% blood meal. There is evidence that a high level of leucine may elevate the isoleucine requirement. Rerat et al. (1975) observed t hat the addition of synthetic isoleucine to raise the isoleucine c o n t e n t from 0.42 to 0.47% in the 12% blood meal diet (containing 2.35% leucine) restored the growth p e r f o r m a n c e and feed intake of gilts to levels comparable to those achieved with the diet containing no bl ood meal. Taylor et al. (1977a), in determining the isoleucine r e q u i r e m e n t of grower pigs to be 0.44%, f o u n d no evidence of a leucine X isoleucine interaction at levels of 1.2% or 1.5% leucine. Later, however, Taylor et al. (1977b) f o u n d that an interaction did exist at a level of 2.0% leucine and this interaction i n f u e n c e d growth performance. Thus it appears t ha t at a level between 1.5 and 2.0% leucine an isoleucine X leucine interaction may affect growth performance. In E x p e r i m e n t 3 the addition o f 0.1% isoleucine to the 12% blood meal diet containing 1.75% leucine improved the growth per f or m ance o f grower pigs but did n o t completely restore the feed intake and growth rate to those of pigs given no blood meal. D'Mello and Lewis (1970) f ound t h a t valine as well as isoleucine was required to alleviate the growth depression caused by an excess of leucine in chick diets which were marginally adequate in both isoleucine and valine. In E x p e r i m e n t 3, the 12% blood meal diet contained much more valine than the level o f 0.50% r e c o m m e n d e d for grower pigs by the National Research Council (1968) and it is unlikely that valine became limiting in the 12% blood meal diet. The gross energy c o n t e n t of blood meal is similar to the figure of 23.9 MJ/kg dry matter, but the DE value de t e r m ined in E x p e r i m e n t 4 is much higher than the value of 12.3 MJ/kg dry matter, both of which were report ed by the National Research Council (1968). However, the DE values of the National Research Council (1968) were of t e n derived indirectly from total digestible nutrients through regression equations. Miller (1977) f o u n d t hat the DE c o n t e n t of a diet t e n d e d to increase when blood meal replaced corn starch, indicating a high DE c o n t e n t in blood meal. In our e x p e r i m e n t the SE of the DE c o n t e n t of blood meal was quite large. This may have been due to the low level (10%) of inclusion of blood meal in the basal diet. Morgan et al. (1975), when using an inclusion level of 20%, f o un d that the SE of the DE c o n t e n t of grass meal was of similar magnitude when expressed as a percentage of the DE content. The results o f these experiments indicate that ring-dried blood meal can be used in grower/finisher diets at levels greater than the presently recomm en d ed levels of 2--3%. At much higher levels of blood meal (9--12%), feed intake and growth p e r f o r m a n c e are depressed, particularly when pigs are fed
200
ad libitum. The depression in feed intake and growth performance observed with high blood meal diets is primarily due to an isoleucine deficiency caused by an excess of dietary leucine in these diets and is not overcome by artificial flavour. However, this is not likely to cause any adverse effects on growth performance or feed intake over the 0--6% range at which blood meal is suggested to be used in practical pig diets. ACKNOWLEDGEMENTS
We wish to thank the following staff of the Department of Agriculture, Victoria: Mr. D. Curic and Mr. R. Biden for the management of the pigs, Mr. C. Rayner, Chemist, and Mr. R. Jardine, Biometrician. REFERENCES Association of Official Analytical Chemists, 1975. Official Methods of Analysis of the A.O.A.C., 12th Edn., Washington, D.C., pp. 130, 135--136. Batterham, E.S. and Manson, M.B., 1970. A nutritional evaluation of diets containing meat meal for growing pigs. 7. The value of meat meal as a protein supplement to barley, oats, sorghum and wheat based diets. Aust. J. Exp. Agric. Anita. Husb., 10: 539--543. Becker, D.E., Smith, I.D., Terrill, S.W., Jensen, A.H. and Norton, H.W., 1963. Isoleucine need of swine at two stages of development. J. Anita. Sci., 22: 1093--1096. D'Mello, D.P.F. and Lewis, D., 1970. Amino acid interactions in chick nutrition. 2. Interrelationships between leucine, isoleucine and valine. Br. Poult. Sci., 11: 313--323. Duncan, D.B., 1955. Multiple range and multiple F tests. Biometrics, 11: 1--42. Fox, M., 1971. Nutritional Evaluation of Meat and Bone Meal. Victorian Department of Agriculture, Division of Agricultural Chemistry. Divisional Report No.1. Gutteridge, J.S. and Trapnell, M., 1972. Feeding of pigs. J. Agric. (Victoria, Aust.), 70: 115--123. Hines, R.H., 1972. Flavoured feed attracts pigs to starter rations. Pig Farmer, 6: 193--197. Miller, E.R., 1977. Formulating swine, poultry rations using flash-dried blood meal. Feedstuffs, 49: 16; 22--23. Morgan, D.J., Cole, D.J.A. and Lewis, D., 1975. Energy values in pig nutrition. 1. The relationship between digestible energy, metabolizable energy and total digestible nutrient values of a range of feedstuffs. J. Agric. Sci., Camb., 84: 7--17. National Research Council, 1968. Nutrient Requirements of Domestic Animals. No.2. Nutrient Requirements of Swine. Publ. National Research Council, Washington, D.C., No. 1599, pp. 27--28. Rerat, A., Henry, Y. and Bourdon, D., 1975. Valeur nutritive de la farine de sang en remplacement du tourteau de soja dans les regimes du porc en croissance -- finition. Journ. Rech. Porcine, France, 1975, pp. 45--52. Taylor, S.J., Cole, D.J.A. and Lewis, D., 1977a. The isoleucine requirement of the growing pig. Anim. Prod., 2 4 : 1 3 7 - - 1 3 8 (abstr.). Taylor, S.J., Cole, D.J.A. and Lewis, D., 1977b. An interaction of leucine, isoleucine and valine in the diet of the growing pig. Proc. Nutr. Soc., 36: 36A (abstr.). Wahlstrom, R.C. and Libal, G.W., 1977. Dried blood meal as a protein source in diets for g r o w i n g - finishing swine. J. Anim. Sci., 44: 778--783.
BLOOD MEAL AS A SOURCE OF PROTEIN FOR GROWER/FINISHER PIGS
R.H. KING and R.G. CAMPBELL Department o f Agriculture, Animal Research Institute, Werribee, Victoria, 3030 (Australia) (Received 15 November 1977)
ABSTRACT King, R~I. and Campbell, R.G., 1978. Blood meal as a source of protein for grower/finisher pigs. Anita. Feed Sci. Technol., 3: 191--200. In the first of four experiments five dietary levels of ring-dried blood meal (0, 3.0, 5.9, 8.9 and 11.8%) were used for pigs of 21--70 kg live weight at two levels of feeding (restricted and ad libitum). Pigs receiving either 5.9 or 8.9% blood meal grew more efficiently than pigs receiving either 0 or 11.8%. The feed conversion ratio of pigs given 3.0% blood meal was of intermediate value. There were significant interactions; when feeding was ad libitum, a reduced intake at the higher levels of blood meal resulted in a slower growth rate at the 11.8% level of blood meal, but with restricted feeding, up to 11.8% blood meal could be included without adverse effects on feed intake or growth rate. In the second and third experiments grower pigs fed ad libitum, between 22 and 50 kg live weight, were used to investigate the effects of the addition of a feed flavour or of isoleucine to a diet containing 12% blood meal. Experiment 2 involved two levels of blood meal (0 and 12%) and two levels of a feed flavour (0 and 50 p.p.m.). The feed flavour failed to prevent the reduction in feed intake and growth caused by 12% blood meal. In the third experiment the addition of 0.1% isoleucine to the 12% blood meal diet significantly increased both intake and growth rate but not to the level of a diet containing no blood meal. In Experiment 4 the digestible energy (+ SE) content of blood meal was determined to be 20.8 (-~. 2.15) MJ/kg dry matter. INTRODUCTION B l o o d m e a l is s i m p l y g r o u n d d r i e d b l o o d a n d is a r i c h s o u r c e o f p r o t e i n a n d m o s t a m i n o acids, p a r t i c u l a r l y l y s i n e . A l t h o u g h b l o o d m e a l has b e e n w i d e l y u s e d as a p r o t e i n s o u r c e f o r pigs, it has g e n e r a l l y b e e n r e c o m m e n d e d t h a t i t s h o u l d b e l i m i t e d t o a b o u t 3% i n pig d i e t s t o a v o i d p r o b l e m s o f p o o r palatability (Gutteridge and Trapnell, 1972). I n t h e p a s t , b l o o d m e a l has b e e n d r i e d b y c o n v e n t i o n a l v a t - d r y i n g p r o c e dures, resulting in a p r o d u c t of p o o r p a l a t a b i l i t y and with a low availability o f l y s i n e . H o w e v e r , n e w e r flash d r y i n g p r o c e d u r e s , i n c l u d i n g b o t h t h e ringdrying process and the rotary s t e a m - d r y i n g process, have i m p r o v e d b o t h the p a l a t a b i l i t y a n d l y s i n e b i o a v a i l a b i l i t y o f b l o o d m e a l (Miller, 1 9 7 7 ) . R e c e n t e x p e r i m e n t s h a v e s h o w n t h a t levels m u c h h i g h e r t h a n t h e p r e v i o u s l y r e c o m -
192
mended level of 3% can be used for pigs without deleterious effects on feed intake or growth performance (Rerat et al., 1975), although Wahlstrom and Libal (1977) found that 8% blood meal significantly reduced the feed intake and growth rate of grower pigs. Becker et al. (1963) reported that pigs given a 15% blood meal diet grew satisfactorily provided that the isoleucine content of the diet was adequate. Blood meal contains a high level of leucine and there is some evidence that a high level of dietary leucine may elevate the isoleucine requirement (Taylor et al., 1977b). This paper reports four experiments to compare the performance of pigs given various amounts of blood meal and to determine the extent to which palatability and the level of leucine may limit the level of inclusion of blood meal in pig diets. In Experiment 1 the performance of grower/finisher pigs was used to compare diets with increasing levels of blood meal. The aims of Experiments 2 and 3 were to investigate the effect of adding a feed flavour or isoleucine to high blood meal diets. The digestible energy (DE} c o n t e n t of blood meal was determined in the fourth experiment. MATERIALS AND METHODS Animals
All the pigs were entire males selected from a minimal disease herd; they were Large White X (Large White X Berkshire). At 8 weeks of age and about 18 kg live weight the pigs were allocated to individual pens, 1.8 m X 0.7 m, in a fully enclosed but unheated piggery. In Experiment 1, experimental diets were given and observations began when individual pigs reached 21 kg live weight {mean 20.9 + 0.1 kg). In Experiments 2 and 3, experimental diets were given and observations began when individual pigs reached 22 kg live weight (means 22.2 -+ 0.2 kg and 22.1 + 0.2 kg, respectively). Design and treatments
Experiments 1 and 2 were factorial experiments. Sixty pigs were stratified according to live weight into six blocks o f ten pigs in Experiment 1. The experiment involved five levels of blood meal (0, 3.0, 5.9, 8.9 and 11.8%) and two levels of feeding (ad libitum and restricted}. In Experiment 2, 24 pigs were stratified according to live weight into six blocks of four pigs. The factors were blood meal (0 and 12.0%} and a feed flavour (0 and 50 p.p.m.). In each experiment the treatments were arranged in a randomized block design and each treatment had six replicates. Experiment 3 was of randomized block design with six pigs on each of three treatments, these being 0 and 12% blood meal and 12% blood meal supplemented with isoleucine. Diets
The diets (Table I) were formulated to be isonitrogenous and isocaloric
19.7 14.3 ± 0.09 0.90 0.81 0.71 1.30 0.93
Analysis Crude protein 3 D i g e s t i b l e e n e r g y +- S E ( M J / k g ) 4 Lysine 5 Available lysine 5 Isoleucine 5 Leucine s Valine s 19.8 1 5 . 2 -+ 0 . 1 1 0.97 0.88 0.64 1.41 1.03
3.0 77.25 9.0 7.5 2.2 0.3 --0.5 0.25
2
19.5 1 5 . 2 -+ 0 . 1 4 1.04 0.94 0.57 1.51 1.11
5.9 77.25 6.0 5.0 2.4 1.2 1.0 0.5 0.5 0.25
3
19.7 15.0 ± 0.07 1.11 1.01 0.50 1.63 1.20
8.9 77.25 3.0 2.5 3.5 1.9 1.5 0.5 0.5 0.25
4
19.4 14.9 + 0.07 1.17 1.08 0.44 1.73 1.28
11.8 77.25 --4.7 2.5 2.0 1.0 0.5 0.25
5
18.7 15.1 ± 0.17 0.90 0.81 0.71 1.30 0.93
-77.25 12.0 10.0 ----0.5 0.25
6
19.0 1 4 . 6 +~ 0 . 1 4 1.19 1.09 0.44 1.75 1.30
12.0 77.25 --7.0 -2.0 1.0 0.5 0.25
8
J Blood meal was dried by the ring-drying process. 2 T h e p r e m i x p r o v i d e d t h e f o l l o w i n g n u t r i e n t s ( p e r k g air d r y d i e t ) : v i t a m i n s ; A 3 8 3 0 i.u., D 3 3 3 0 i.u., E 3 3 i.u., K 6 6 0 p g , r i b o f l a v i n 3 . 3 m g , n i a c i n 1 6 . 5 m g , p a n t o t h e n i c a c i d 5 . 5 m g , p y r i d o x i n e 1.1 m g , B12 17 p g , b i o t i n 5 6 p g , c h o l i n e 1 1 0 0 rag; m i n e r a l s ; F e 8 8 m g , Z n 55 rag, M n 22 m g , C u 6 . 6 m g , Co 0 . 6 6 m g , I 0 . 2 2 rag, Se 0 . 1 1 rag. 3 Estimated for each diet by laboratory analyses. 4 D e t e r m i n e d in t h e d i g e s t i b i l i t y s t u d y w h e r e D E = g r o s s e n e r g y × d r y m a t t e r d i g e s t i b i l i t y ( B a t t e r h a m a n d M a n s o n , 1 9 7 0 ) . s Calculated for each diet from the analyses of ingredients.
-77.25 12.0 10.0 ----0.5 0.25
1
Diet
1, 2 a n d 3 (air d r y b a s i s )
Constituent Blood meal 1 Wheat Soya bean meal Meat and bone meal Starch Tallow Boneflour Limestone Mineral/vitamin premix 2 Salt
C o m p o s i t i o n o f d i e t s u s e d in E x p e r i m e n t s
TABLE I
~D
194
in each ex p er imen t with an equal p r o p o r t i o n of wheat in each diet. Diets 7 and 9 were similar in composition to Diets 6 and 8, respectively, except that 50 p.p.m, o f feed flavour (Firanor No. 3, Firmenich et Cie, Geneva) was included. Diet 10 was similar in composition to Diet 8 except that 0.1% synthetic isoleucine was added. Diets 1--5 were used in E x p e r i m e n t 1, Diets 6--9 in E x p e r i m e n t 2 and Diets 6, 8 and 10 in Experiment 3.
Feeding and management Pigs were weighed weekly and the daily feed intake of those fed on a restricted basis was subsequently adjusted. Intakes were increased according to live weight f r o m 1.0 to 2.3 kg meal daily as live weight increased from 20 to 63 kg. All pigs in Experiments 2 and 3 were fed ad libitum and the feed intake of all pigs offered diets ad libitum was recorded weekly. Pigs in E x p e r i m e n t 1 were slaughtered at 70 kg live weight (mean 69.6 -+ 0.2 kg) and pigs in Experiments 2 and 3 were slaughtered at 50 kg live weight (means 51.1 + 0.2 kg and 51.2 + 0.4 kg, respectively). A b o u t 24 hours after slaughter the depth of backfat of each carcass was measured with an optical probe at 6.5 cm from the midline at the level of the last rib. The left ham was removed from each carcass by a cut at right angles to the b o d y and passing through the e x t r e m e anterior section of the femur. The p r o p o r t i o n of lean meat, fat and bone was determined by dissection.
Digestibility trials In each of two trials, ten entire males were confined to metabolism cages in a r o o m kept at about 20°C. The pigs were allowed ten days to become accustomed to the cages, after which t he y were weighed. In the first trial, two pigs were r a n d o m l y allotted to each of Diets 1--5 (Table I) for a 14-day period. At the end of this period the pigs were weighed and random l y re-allotted to the diets for a second 14-day period. In the second trial, the 10 pigs were given either Diet 6 or 8 to obtain estimates of the DE c o n t e n t of these diets. The average initial live weights of the pigs were 21.0 + 1.9 kg and 40.7 -+ 1.4 kg in Trials 1 and 2, respectively. Dry meal equivalent to 3.5% of the initial live weight in each test period was given to each pig daily, water (2/1, 2/1, w/w) being mixed with the meal. The faeces from each pig were collected daily on the last five days of each test period and stored at 1°C. At the end of each collection period, the combined daily faeces from each pig were weighed, thoroughly mixed and sampled for further analysis. Also in E x p e r i m e n t 4, eight estimates of the DE c o n t e n t of blood meal were obtained. Eight pigs, weighing initially 30.9 + 1.5 kg, were given either a basal diet of wheat or a test diet in which 10% of the basal diet was replaced by blood meal in an 8 X 2 factorial experiment. The basal diet contained 96.2% wheat, 2.0% steamed boneflour, 1.0% ground limestone, 0.5%
195
m i n e r a l a n d v i t a m i n p r e m i x a n d 0.3% salt. M a n a g e m e n t a n d c o l l e c t i o n proc e d u r e s were similar to t h o s e d e s c r i b e d a b o v e a n d the D E c o n t e n t o f b l o o d m e a l was c a l c u l a t e d b y difference.
Chemical analyses T h e gross e n e r g y of all diets and freeze dried faeces s a m p l e s c o l l e c t e d in E x p e r i m e n t 4 was d e t e r m i n e d in an a d i a b a t i c b o m b c a l o r i m e t e r . P r o x i m a t e analysis o f diets and feeds was m a d e b y s t a n d a r d p r o c e d u r e s ( A s s o c i a t i o n o f Official A n a l y t i c a l Chemists, 1975). T h e a m i n o acid c o m p o s i t i o n a n d Silcock available lysine c o n t e n t s o f t h e feeds w e r e d e t e r m i n e d b y m e t h o d s d e s c r i b e d b y F o x (1971).
Statistical analysis G r o w t h p e r f o r m a n c e , dally feed i n t a k e and carcass q u a l i t y d a t a were subj e c t e d to s t a n d a r d analysis o f v a r i a n c e p r o c e d u r e , and significant d i f f e r e n c e s were e x a m i n e d b y D u n c a n ' s m u l t i p l e r a n g e t e s t ( D u n c a n , 1955). RESULTS T h e c r u d e p r o t e i n , essential a m i n o acid and available lysine c o n t e n t o f b l o o d m e a l are r e p o r t e d in T a b l e II.
TABLE II Crude protein and essential amino acid analyses of blood meal (air dry basis) Constituent
Percentage of feed
Percentage of crude protein
Crude protein Arginine Cystine Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Tyrosine Valine Available lysine
88.5 3.58 1.23 4.77 1.15 10.26 7.64 1.30 5.91 4.57 1.90 2.59 7.74 7.15
4.05 1.39 5.39 1.30 11.59 8.63 1.47 6.68 5.16 2.15 2.93 8.75 8.08
196
Experiment 1 Pigs r e c e i v i n g e i t h e r 5 . 9 o r 8 . 9 % b l o o d m e a l g r e w pigs given either the highest or lowest level of blood feed conversion ratio of pigs given 3.0% blood meal meal had no effect on any of the carcass parameters had more backfat.
TABLE
more efficiently than meal (Table III). The was intermediate. Blood but pigs fed ad libitum
III
Experiment 1. Main effects of blood meal level and feeding level on growth performance and carcass characteristics of grower/finisher pigs (21--70 kg live weight)
Main effect
Feed conversion ratio
Backfat thickness (mm)
Lean meat in ham (%)
Blood meal level (%) 0 3.0 5.9 8.9 11.8
2.87 cd~ 2.79 bc 2.64 a 2.73 ab 2.91 d
19.2 20.2 19.6 18.4 19.2
66.3 65.3 66.3 65.5 64.2
Feeding level Ad libitum Restricted
2.94 b 2.64 a
21.1 b 17.6 a
65.5 65.5
Coefficient of variation (%)
4.8
15.6
3.1
1 In this and subsequent tables, within columns, for each main effect, means with different superscript letters are significantly different at the 5% level of probability (Duncan, 1955); in the absence of superscripts means are not significantly different.
T h e r e w e r e s i g n i f i c a n t i n t e r a c t i o n s b e t w e e n f e e d i n g level a n d b l o o d m e a l level ( T a b l e I V ) ; a r e d u c t i o n in f e e d i n t a k e a t t h e h i g h e r l e v e l s o f b l o o d m e a l retarded growth rate at the 11.8% blood meal level when feeding was ad libitum but not when it was restricted.
Experiment 2 Pigs g i v e n d i e t s w i t h o u t b l o o d m e a l a t e m o r e , g r e w f a s t e r a n d t e n d e d t o h a v e a b e t t e r f e e d c o n v e r s i o n r a t i o t h a n p i g s g i v e n 1 2 % b l o o d m e a l ( T a b l e V). The feed flavour had no effect on the intake, growth performance or carcass c h a r a c t e r i s t i c s o f t h e pigs.
197
TABLE IV Experiment 1. Feed intake and growth rate of pigs grown from 21 to 70 kg live weight as influenced by blood meal level and feeding level Blood meal level (%)
Feed intake (kg/day) /kt libitum Restricted Growth rate (g/day) Ad libitum Restricted
0
3.0
5.9
8.9
11.8
2.30
2.27
2.21
2.13
1.99
1.64
1.64
1.64
1.65
1.62
760
774
796
756
641
606
623
655
628
598
L.S.D.
(P = 0.05)
Between any two means
Between any two differences
0.12
0.17
54
77
TABLE V Experiment 2. Main effects of a feed flavour on growth performance and carcass characteristics of grower pigs (22--50 kg live weight) Main effect
Blood meal level (%) 0 12
Growth rate (g/day)
Feed conversion ratio
Feed intake (kg/day)
Backfat thickness (ram)
Lean meat in ham (%)
776 a 600 b
2.87 3.01
2.23 a 1.80 b
16.8 15.0
63.6 64.4
2.93 2.95
1.99 2.05
15.8 16.0
64.2 63.8
5.8
6.5
14.5
2.3
Feed flavour level (ppm) 0 680 50 695 Coefficient of variation (%)
6.0
Experiment 3 A s u m m a r y o f t h e r e s u l t s is g i v e n in T a b l e V I . T h e a d d i t i o n o f 0 . 1 % isoleucine to the 12% blood meal diet increased both feed intake and growth rate but not to the level of the diet containing no blood meal. Feed convers i o n r a t i o a n d c a r c a s s c h a r a c t e r i s t i c s w e r e n o t a f f e c t e d b y t h e t r e a t m e n t s alt h o u g h pigs g i v e n 1 2 % b l o o d m e a l t e n d e d t o h a v e a p o o r e r f e e d c o n v e r s i o n r a t i o a n d less b a c k f a t .
198
TABLE VI Experiment 3. Effects of isoleucine supplementation of a high blood meal diet on growth performance and carcass characteristics of grower pigs (22--50 kg live weight) Treatment
0% blood meal 12% blood meal 12% blood meal + 0.1% isoleucine Coefficient of variation (%)
Growth rate (g/day)
Feed conversion ratio
Feed intake (kg/day)
Backfat thickness (mm)
Lean meat in ham (%)
782 a 579 c
2.87 3.00
2.24 a 1.73 c
17.6 13.9
63.3 64.9
687 b
2.88
1.97 b
16.9
64.5
4.9
7.6
7.9
15.3
2.7
Experiment 4 The digestible energy c o n t e n t s of Diets 1--8 are i n c l u d e d in Table I. The gross energy c o n t e n t o f b l o o d meal was 24.7 M J / k g d r y m a t t e r and the average DE c o n t e n t s (+ SE) o f b l o o d meal and the basal w h e a t diet were 20.8 (-+ 2.15) and 16.0 (_+ 0.18) M J / k g d r y m a t t e r , respectively. DISCUSSION The results o f the first e x p e r i m e n t indicate t h a t r e p l a c e m e n t of m o r e t h a n 75% o f s o y a bean meal and m e a t and b o n e meal with b l o o d meal decreased feed intake and g r o w t h rate w h e n pigs were fed ad l i b i t u m (Table IV). However, feed intake and g r o w t h rate were n o t adversely a f f e c t e d b y b l o o d meal w h e n pigs were fed o n a restricted basis. T h e DE c o n t e n t o f Diet 1 was l o w e r t h a n t h a t o f Diets 2--5 and the a p p a r e n t l y inferior feed c o n v e r s i o n ratio of Diet 1 was o n l y a reflection o f the l o w e r DE c o n t e n t o f this diet. T h e high lysine c o n t e n t (1.17%) of the diet c o n t a i n i n g 11.8% b l o o d meal in Experim e n t 1 m a y have c o n t r i b u t e d t o the p o o r e r feed c o n v e r s i o n ratio o f pigs given this diet. The feed c o n v e r s i o n e f f i c i e n c y o f pigs o f a similar live-weight range was r e d u c e d w h e n d i e t a r y lysine was raised f r o m 1.02% to 1.2% (R.G. Campbell, personal c o m m u n i c a t i o n ) . Wahlstrom and Libal ( 1 9 7 7 ) f o u n d t h a t m o r e t h a n 6% steam-dried b l o o d meal r e d u c e d the feed intake and g r o w t h rate o f g r o w e r pigs fed ad libitum. However, in o u r first e x p e r i m e n t , w h e n feeding was ad libitum, 8.9% b l o o d meal had n o adverse effects on g r o w t h rate or feed c o n v e r s i o n e f f i c i e n c y alt h o u g h feed intake was depressed. O u r observations w h e n feeding was restricted agree with t h o s e of R e r a t et al. ( 1 9 7 5 ) w h o fed b a r r o w s and gilts on a restricted basis b e t w e e n 25 and 60 kg live weight. T h e r e was little difference in the g r o w t h p e r f o r m a n c e o f b a r r o w s given 0 or 12% b l o o d meal, b u t gilts t e n d e d to eat less and grow slower w h e n given the 12% b l o o d meal diet.
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Feed f a v o u r s have been used with varying success to increase the feed consumption and growth rate of pigs, particularly young pigs (Hines, 1972). However, the addition of a feed flavour did n o t overcome the reduced voluntary feed intake o f pigs receiving a diet containing 12% blood meal, nor did it increase the feed c o n s u m p t i o n of pigs given diets w i t hout blood meal. The results of the third e x p e r i m e n t indicate an isoleucine deficiency in the diet containing 12% blood meal. There is evidence that a high level of leucine may elevate the isoleucine requirement. Rerat et al. (1975) observed t hat the addition of synthetic isoleucine to raise the isoleucine c o n t e n t from 0.42 to 0.47% in the 12% blood meal diet (containing 2.35% leucine) restored the growth p e r f o r m a n c e and feed intake of gilts to levels comparable to those achieved with the diet containing no bl ood meal. Taylor et al. (1977a), in determining the isoleucine r e q u i r e m e n t of grower pigs to be 0.44%, f o u n d no evidence of a leucine X isoleucine interaction at levels of 1.2% or 1.5% leucine. Later, however, Taylor et al. (1977b) f o u n d that an interaction did exist at a level of 2.0% leucine and this interaction i n f u e n c e d growth performance. Thus it appears t ha t at a level between 1.5 and 2.0% leucine an isoleucine X leucine interaction may affect growth performance. In E x p e r i m e n t 3 the addition o f 0.1% isoleucine to the 12% blood meal diet containing 1.75% leucine improved the growth per f or m ance o f grower pigs but did n o t completely restore the feed intake and growth rate to those of pigs given no blood meal. D'Mello and Lewis (1970) f ound t h a t valine as well as isoleucine was required to alleviate the growth depression caused by an excess of leucine in chick diets which were marginally adequate in both isoleucine and valine. In E x p e r i m e n t 3, the 12% blood meal diet contained much more valine than the level o f 0.50% r e c o m m e n d e d for grower pigs by the National Research Council (1968) and it is unlikely that valine became limiting in the 12% blood meal diet. The gross energy c o n t e n t of blood meal is similar to the figure of 23.9 MJ/kg dry matter, but the DE value de t e r m ined in E x p e r i m e n t 4 is much higher than the value of 12.3 MJ/kg dry matter, both of which were report ed by the National Research Council (1968). However, the DE values of the National Research Council (1968) were of t e n derived indirectly from total digestible nutrients through regression equations. Miller (1977) f o u n d t hat the DE c o n t e n t of a diet t e n d e d to increase when blood meal replaced corn starch, indicating a high DE c o n t e n t in blood meal. In our e x p e r i m e n t the SE of the DE c o n t e n t of blood meal was quite large. This may have been due to the low level (10%) of inclusion of blood meal in the basal diet. Morgan et al. (1975), when using an inclusion level of 20%, f o un d that the SE of the DE c o n t e n t of grass meal was of similar magnitude when expressed as a percentage of the DE content. The results o f these experiments indicate that ring-dried blood meal can be used in grower/finisher diets at levels greater than the presently recomm en d ed levels of 2--3%. At much higher levels of blood meal (9--12%), feed intake and growth p e r f o r m a n c e are depressed, particularly when pigs are fed
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ad libitum. The depression in feed intake and growth performance observed with high blood meal diets is primarily due to an isoleucine deficiency caused by an excess of dietary leucine in these diets and is not overcome by artificial flavour. However, this is not likely to cause any adverse effects on growth performance or feed intake over the 0--6% range at which blood meal is suggested to be used in practical pig diets. ACKNOWLEDGEMENTS
We wish to thank the following staff of the Department of Agriculture, Victoria: Mr. D. Curic and Mr. R. Biden for the management of the pigs, Mr. C. Rayner, Chemist, and Mr. R. Jardine, Biometrician. REFERENCES Association of Official Analytical Chemists, 1975. Official Methods of Analysis of the A.O.A.C., 12th Edn., Washington, D.C., pp. 130, 135--136. Batterham, E.S. and Manson, M.B., 1970. A nutritional evaluation of diets containing meat meal for growing pigs. 7. The value of meat meal as a protein supplement to barley, oats, sorghum and wheat based diets. Aust. J. Exp. Agric. Anita. Husb., 10: 539--543. Becker, D.E., Smith, I.D., Terrill, S.W., Jensen, A.H. and Norton, H.W., 1963. Isoleucine need of swine at two stages of development. J. Anita. Sci., 22: 1093--1096. D'Mello, D.P.F. and Lewis, D., 1970. Amino acid interactions in chick nutrition. 2. Interrelationships between leucine, isoleucine and valine. Br. Poult. Sci., 11: 313--323. Duncan, D.B., 1955. Multiple range and multiple F tests. Biometrics, 11: 1--42. Fox, M., 1971. Nutritional Evaluation of Meat and Bone Meal. Victorian Department of Agriculture, Division of Agricultural Chemistry. Divisional Report No.1. Gutteridge, J.S. and Trapnell, M., 1972. Feeding of pigs. J. Agric. (Victoria, Aust.), 70: 115--123. Hines, R.H., 1972. Flavoured feed attracts pigs to starter rations. Pig Farmer, 6: 193--197. Miller, E.R., 1977. Formulating swine, poultry rations using flash-dried blood meal. Feedstuffs, 49: 16; 22--23. Morgan, D.J., Cole, D.J.A. and Lewis, D., 1975. Energy values in pig nutrition. 1. The relationship between digestible energy, metabolizable energy and total digestible nutrient values of a range of feedstuffs. J. Agric. Sci., Camb., 84: 7--17. National Research Council, 1968. Nutrient Requirements of Domestic Animals. No.2. Nutrient Requirements of Swine. Publ. National Research Council, Washington, D.C., No. 1599, pp. 27--28. Rerat, A., Henry, Y. and Bourdon, D., 1975. Valeur nutritive de la farine de sang en remplacement du tourteau de soja dans les regimes du porc en croissance -- finition. Journ. Rech. Porcine, France, 1975, pp. 45--52. Taylor, S.J., Cole, D.J.A. and Lewis, D., 1977a. The isoleucine requirement of the growing pig. Anim. Prod., 2 4 : 1 3 7 - - 1 3 8 (abstr.). Taylor, S.J., Cole, D.J.A. and Lewis, D., 1977b. An interaction of leucine, isoleucine and valine in the diet of the growing pig. Proc. Nutr. Soc., 36: 36A (abstr.). Wahlstrom, R.C. and Libal, G.W., 1977. Dried blood meal as a protein source in diets for g r o w i n g - finishing swine. J. Anim. Sci., 44: 778--783.