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Protein and energy utilization by the insect, argyrotaenia velutinana (walker) fed diets containing graded levels of an amino acid mixture
Comp. Bioche.t. Physiol., Vol. 52A. pp. 615 to 618. Pergamon Press. Printed i. Great Britain
PROTEIN AND ENERGY UTILIZATION BY T H E INSECT, ARGYROTAENIA VELUTINANA (WALKER),* FED DIETS CONTAINING GRADED LEVELS OF AN AMINO ACID MIXTURE']" G. Y. Lu:~, J. D. GARLICH§AND G. C. RocK:~ Department of Entomology, North Carolina State University, Raleigh, NC 27607, U.S.A. (Received 19 October 1974) Abstract--l. Isocaloric diets containing graded levels of a balanced amino acid mixture (AAM) were fed to Argyrotaenia velutinana from the age of newly-hatched larvae to day 18. Feed consumption and larval weight gain increased with increasing amounts of AAM up to 3'6% of the diet. 2. The % of the ingested dietary nitrogen and energy recovered in the carcass at 18 days was highest for the larvae fed the diet containing 3.0% AAM. 3. Carcass composition increased in nitrogen and decreased in lipid with increasing dietary protein: calorie ratio. Carcass composition changes are similar to changes in another uricotelic organism, the birds.
INTRODUCTION NUTRITIONAL studies with homeotherms have shown that in general the dietary protein:calorie ratio influences feed consumption, growth rate, efficiency of energy and protein utilization, and carcass composition. Optimum protein:calorie ratios have been established experimentally for chicks (Donaldson et al., 1956; Velu et al., 1971), turkeys (Blixler et al., 1969) ducks (Scott et al., 1959), rats (Hegsted & Neff, 1970); Yoshida et al., 1957), pigs (Clawson et al., 1962), and lambs (Jones & Hogue, 1960). The work reported here contains the results of experiments designed to investigate the optimal level of dietary protein for the phytophagous insect Argyrotaenia velutinana (Walker). The larvae were fed isocaloric diets containing graded levels of a balanced amino acid mixture. Protein and energy consumption, utilization, growth rate, and carcass composition were determined.
amount of a heat sterilized diet. The larvae were reared xenically and antimicrobial agents were added to the diets. The larvae were allowed to feed and develop for 18 days. The insects were reared at 27 ___0"5°C with a 16hr illumination period/day.
MATERIALS AND METHODS Insect rearing The rearing techniques and methods for maintaining laboratory colonies and preparing chemically defined diets for A. velutinana were essentially the same as previously reported by Rock & King (1966, 1967). Egg masses were surface sterilized by immersion in a 10% formalin solution for 20min, and 5 newly-hatched larvae were transferred to a capped l oz plastic jelly cup containing a known * Lepidoptera: Tortricidae. t This investigation was supported in part by research grant AI-08633 from the National Institute of Allergy and Infectious Diseases, National Institutes of Health. Paper No. 4488 of the Journal Series of the North Carolina Agricultural Experiment Station, Raleigh, NC. :[:Department of Entomology. § Department of Poultry Science. 615
Table 1. Composition of the amino acid diet for A. velutinana at a 3% level of dietary protein Compoo£tion
S/IOOs dte¢ kmiuo 8 c l d
19 smlno a c l d s I ( L - a l l o f r e e )
3.000
Dmxcrox 2
5.000
Choleoterol
0 • 200
S a f f l o w e r o£1
0.300
Wesson u l t W 3
1.200
Z~'I2~uSO 4
0.005
,,*04,,%0
o.o~o
B-vttmain a/xture I
0.142
l ~ e e n 80
0.300
Ant:tmlcroblal a s e n t s 4
2 al
~r
3.00
2 M KOII to Sive pH 6.2 D i s t i l l e d wster Co 1(]08
~For composition, see Rock & King (1967a). 2 The purified amino acid mixture was added to or omitted from the diet at the expense of dextrose. 3 Osborne, T. B. & Mendel, L. B. (1932) A modification of the Osborne-Mendel salt mixture containing only inorganic constituents. Science, N.Y. 75, 339. 4Sorbic Acid, 20'0g; methyl parasept (methyl para-hydroxybenzoate), 15-0g; and ethyl alcohol, 170.0ml.
816
G . Y . L . , J. D. GARLICH AND G. C. ROCK
Diet composition The composition of the amino acid diet for rearing A. velutinana is shown in Table 1. The pattern of the amino acids in this dietary mixture was similar to the amino acid pattern found in the carcass of A. velutinana (Rock & King, 1966). Feeding tests with A. velutinana had shown that an amino acid mixture patterned after that found in the carcass would support optimum larval growth (Rock & King, 1967/)). The different amino acid mixtures were essentially isocaloric. Changes in the calorie:protein ratio were accomplished by altering the proportions of the amino acid mixtures and dextrose, while the level of other nutrients remained constant. The major dietary constituents were obtained from Nutritional Biochemicals Corporation, Cleveland, Ohio. Weight 9ain,food consumption, nitrogen and lipid percentage measurements All results were expressed on the dry weight basis. The dry weight was determined by drying 16 hr at 100°C. The dry weight of food introduced was calculated by using the mean ~o of dry matter from 5 aliquots which had been dried to a constant weight. At the end of the feeding period, the left-over food was separated from the feces and dried to a constant weight. The quantity of food eaten was calculated by subtracting the dry weight of uneaten food from the dry weight of the food originally introduced. The dry carcasses of the larvae were crushed into small pieces and were extracted with redistilled petroleum ether
in a soxhlet apparatus for at least 3 hr. The ether, containing the neutral lipids from the larvae, was transferred to tared vials and evaporated with nitrogen. The lipid was determined gravimetrically. Although this procedure does not remove phospholipid, it does estimate the lipid stored in fat bodies. The dry fat-free larval carcasses were transferred to a 30 ml Kjeldahl flask for nitrogen determination (McKenzie & Wallace, 1953). Carcass energy was calculated by usingthe method of Fraps & Carlyle (1939). Chitin was not included in this calculation. Dietary metabolizable energy was calculated by a method similar to that of Scott et al. (1969). Carcass protein was defined as N x 6.25. It is recognized however, that some of this nitrogen was present in the chitinous exosketon. Data are not corrected for sex differences since sex could not be determined at the time an experiment was completed. Each experiment had 4 replicates with 15-20 individuals/replicate. The results were analyzed statistically using analysis of variance (Steel & Torrie, 1960). Differences between individual treatment means were tested for significance by use of Duncan's Multiple F-Test (Duncan, 1955).
RESULTS Larval feed c o n s u m p t i o n a n d weight gain were m a x i m u m when the diet contained 3"6~o a m i n o acid mixture (Table 2). The efficiency of feed utilization (carcass dry weight gain: feed ratio) was at a maxi-
Table 2. Performance of A. velutinana fed diets containing graded levels of the amino acid mixture ~ ~ i u o Acid m:f~cure l e v e l X
Dry wc g a i n / l a r v a 2 ms
Feed c o n s ~ p t i n ~ / l a r v a mg
C~in/feed 2
2.4
0.81 a
4.11
3.0
1.S7 ab
6.31
0 . 2 0 ab
3.6
3.22 c
15.10
4.2
2.35 bc
10.31
0 . 2 3 be
4.8
1.6S ab
9.12
0 . 1 8 ab
5.4
2 , 2 1 bc
13.16
0.2S c 0 . 2 1 abe
0.17 a
All values are means of four replicate groups of 18-day old larvae. 2 Means followed by the same letter do not differ significantly (P < 0.05). Table 3. Protein and energy retention by A. velutinana fed diets containing graded levels of amino acid mixture ~ ~Lino a c i d mixture level Z
Consumption
Protein22 m8 x 10
ReCentlon in Carcase
Energy 3 calories
Protein 2 mg x 10 - 2
Energy 4 calorine
Effielency
5
P r o t e i n Energy Z
Z
2.4
75
13
35
4
47
31
3.0
142
19
77
8
54
42
3.6
406
46
141
16
35
35
4.2
317
30
116
12
37
40
4.8
318
26
89
8
28
31
5.4
501
27
118
11
24
41
Means of four replicate groups of eighteen-day old larvae. 2 Protein = N x 6"25. 3 Mg dextrose x 3"65 cal + m g lipid x 9.35 cal + mg amino acid x 3.65 cal (Scott et al., 1969). 4 Carcass energy = mg lipid x 9'35 cal + mg protein x 5'66 cal (Fraps & Carlyle, 1939), carbohydrate (chitin) was not included. 5 Percentage of ingested protein (N x 6"25) and energy recovered in the carcass of 18-day old larvae.
Utilization by insect fed amino acid mixture diets 2(;
) ';o 15
,,=, ,o ,,=, s
0/) 14.8
I I I I I0 20 30 40 ENERGY CONSUMPTION (Colories)
o
I 50
Fig. 1. The relationship between dietary energy consumption and energy recovered in the carcass of the 18-day old larva (A. uelutinana). The numbers in parenthesis beside the circles indicate the percentage of amino acid mixture in the diet. mum for the range of dietary amino acid levels between 3"0 and 4"2~ of the diet. The efficiencies of energy and protein (N x 6.25) utilization are shown in Table 3. A plot of energy recovered as fat and protein in the carcass at 18 days versus metabolizable energy consumed indicated a relationship described by the equation Y+ 0.373 + 0.352X where Y represents energy in the carcass and X represents energy consumed (Fig. 1). The good linear fit (r 2 = 0'93) indicates that over the range of amino acid intakes studied the utilization of energy for carcass deposition was rather constant. The slope of the line indicates that approximately 35~ of the ingested energy can be recovered as productive energy in the form of carcass fat and protein. A plot of protein consumed versus protein recovered in the carcass indicated a rather linear relationship for intake of the diets containing from 2"4 to 4-270 of the amino acid mixture (Fig. 2). At higher levels of dietary amino acid mixture reduced amounts of ingested protein were recovered in the carcass. Larval carcass composition changed in response to the dietary amino acid:calorie ratio (Table 4). Carcass
/
150
,~ 130 "~ ¢= IIC z
(4.2)~
/
50 Y = 22.00 + 0.298X
IO
I
I
I
L1pid 2
2.4
6.9 a
28.5 a
3.0
7.8 b
25.3 abc
3.6
7.0 a
26.8 ab
4.2
7.9 b
23.5 bed
4.8
8.6 b
20.3 d
5.4
8.6 b
2 0 . 8 cd
~All values are means of four replicate groups of eighteen-day old larvae. 2 Means followed by the same letter do not differ significantly (P < 0'05). 31 2$
o
27 '
0
0
23
y
21
0
J r
57
I 6
I I 7 8 NITROGEN, %
I 9
I I0
Fig. 3. The relationship between carcass lipid and nitrogen a s influenced by the dietary protein:calorie ratio. nitrogen increased and carcass lipid decreased with increasing dietary levels of amino acid mixture. A regression equation relating carcass nitrogen and lipid is shown in Fig. 3. Y = 57.96-4.33 X, where Y represents percent carcass lipid and X represents 70 carcass nitrogen. The goodness of linear fit is indicated by an r 2 = 0'956. DISCUSSION
(5 4 ) e
~ 7c
0
Larval composition as % of dry veisht
Nitrosen 2
3.61
014.81
9G
Table 4. The nitrogen and lipid composition of A. velutinana fed diets containing graded levels of amino acid mixture t Amino a c l d =£xl;ure l e v e l %
(4 2)0/
~
>-
617
I
I
o I00 200 300 400 500 PROTEIN CONSUMED(rag x I0 "z)
Fig. 2. The relationship between dietary protein consumed and protein recovered in the carcass of the 18-day old larva (A. velutinana). The numbers in parenthesis indicate the percentage of amino acid mixture in the diet. The equation for the line was calculated for the values represented by circles. The values represented by solid circles were not included in the calculation.
Velu et al. (1971) who studied young chickens stated that the optimum dietary requirement for protein (N x 6"25) from a balanced amino acid mixture must be defined in terms of a specific criterion or response. For" example, they observed that a 20% greater dietary protein content was required to maximize chick weight gain and protein retention and 60~ more to maximize gain:feed ratio and body protein concentration than was required to maximize feed and energy consumption or energy retention. Body fat was maximal at low levels of dietary protein. Also for pigs (Clawson et al., 1962) and rats (Yoshida et al., 1957) the dietary protein:calorie ratio was observed to influence feed consumption and body weight gain. Table 5 summarized the observations on A. oelutinana. In the present study larval feed intake and body weight gain were maximal when the diet contained 3"670 amino acid mixture. At greater levels of
6f8
G.Y. Lll, J. D. GARLICHAND G. C. ROCK Table 5. Response criteria as a function of dietary concentration of the amino acid mixture Criterion
Required amino acid m:txcure co~cengratio~
their response to altered dietary amino acid:calorie ratios. In particular, the carcass composition changes in the larvae are similar to the changes in another uricotelic organism, the birds.
Z Max-/.mal g a i n / f e e d r a t i o
3.0
Haximal veighc gain
3.6
~Y~t
3.6
protein r e t e n t i o n
Haxgmal energy r e t e n t i o n
3.6
14aximal food constBpCion
3.6
l~txi~utl emerg7 consumption
3.6
14ax£eud. body proCe:tn Z
4.8
Hini3um body Lipid Z
4.8
dietary amino acid mixture feed intake and weight gain declined. Velu et al. (1971) observed that the feed intake of chicks also declined when the diet contained high levels of a balanced amino acid mixture. The larvae of A. oelutinana demonstrated a rather constant rate of deposition of ingested energy in the carcass over the entire range of dietary amino acid levels (Fig. 1). This was true despite the differences in feed intake. Velu et al. (1971) reported a similar observation for chicks. Hegsted & Neff (1970) demonstrated that "protein utilization in young rats is constant over an appreciable range of intakes from the maintenance levels to those which allow near maximal growth." Velu et al. (1971) found this to hold true for chicks also. A similar response was obtained with A. oelutinana larvae as shown by the plot of carcass protein content versus protein intake (Fig. 2). A linear equation (r 2 = 0.961), Y = 22'0 + 0"298 X where Y represents carcass protein (N x 6.25) and X represents protein consumed describes amino acid utilization for dietary amino acid levels between 2.4 and 4.2~ of the diet. Within this range 29"8~o of the ingested nitrogen was recovered in the carcass at 18 days. At dietary amino acid levels of 4"8~o and above the efficiency of utilization was less. There was an inverse relationship between the nitrogen and lipid content of the carcass of A. velutinana (Fig. 3). As the nitrogen content of the insect larva increased I~o the lipid content decreased 4.33~. A similar relationship has been reported for the chick (Velu et al., 1971) and the rat (Bender & Miller, 1953). Velu et al. (1971) observed that maximal body protein ~ and minimal body fat occurred in chick which consumed diets containing greater amounts of protein than were required for maximal body weight gain. This was also true for A. velutinana. In chicks (Donaldson et al., 1956; Velu et al., 1971), turkeys (Donaldson et al., 1958) and ducks (Scott et al., 1959) carcass lipid content increased as the dietary protein: calorie ratio decreased. The larvae of A. velutinana exhibited a similar response (Table 4). The results of this study indicate a striking similarity in response between insect larva, A. oelutinana, and certain mammalian and avian species in
REFERENCES
BIXLER E. G., COMBSG. F. & SHAFFNERC. S, (1969) Effect of protein level on carcass composition of turkeys. Poult. Sci. 48, 261-266. BENDER A. E. & MILLER D. S. (1953) Constancy of the N/I-I20 ratios of the rat and its use in the determination of the net protein value. Biochem. J. 53, 7-8. CLAWSON A. J., BLUMER T. N., SMART W . W . G. & BARRICK E. R. (1962) Influence of energy-protein ratio on performance and carcass characteristics of swine. J. Anita. Sci. 21, 62-68. DONALDSON W . E., COMBS G . E. & ROMOSER G . L . (1956) The effect of calorie-protein ratio of the ration on growth, nutrient utilization, and body composition of chicks. Poult. Sci. 35, II00-1105. DONALDSON et al., (1958) Studies on energy levels in poultry rations. Effects of calorie-protein ratio of the ration on growth, nutrient utilization and body composition of poults, ibid 37, 614-619. DUNCAN D. B. (1955) Multiple range and multiple F-tests. Biometries II, 1-42. FRAPS G. S. & CARLYLE E. C. (1939) The utilization of the energy of feed by growing chicks. Tex. Agr. Exp. Sta. Bul. 571. HEGSTEO D. M. & NEFF R. (1970) Efficiency of protein utilization in young rats at various levels of intake. J. Nutr. 100, 1173-1179. JONES J. R. & HOOUE D. E. 0960) Effect of energy level on the protein requirement of lambs fattened with and without stilbestrol. J. Anita. Sci. 19, 1049-1054. MCKENZIE H. A. & WALLACEH. S. (1954) The Kjeldahl determination of nitrogen: A critical study of digestion condition-temperature, catalyst, and oxidizing agent. Aust. J. Chem. 7, 55-70. ROCK G. C. & KING K. W. (1966) Amino Acid composition in hydrolysates of the red-banded leaf roller, Argyrotaenia velutinana (Lepidoptera:Tortricidae) During development. Ann. ent. Soc. Am. 59, 273-275. ROCK G. C. & KING K. W. (1967) Qualitative amino acid requirements of the red-banded leaf roller, Argyrotaenia velutinana. J. Insect Physiol. 13, 59-65. ScoTr M. L., HILL F. W., PARSONS E. H. & BRUCKNER J. H. (1959) Studies on duck nutrition, No. 7. Effect of dietary energy:protein relationships upon growth, feed utilization, and carcass composition in market ducklings. Poult. Sci. 38, 497-507. SCOTT M. L., N~HEIM M. C. & YOUNG R. J. (1969) Nutrition of the chicken. M. L. Scott & Associates. Ithaca, New York. STEEL G. D. & TORRIE J. H. (1960) Principles and Procedures of Statistics. McGraw-Hill, New York. VELU J. G., BAKER D. H. & SCOTT H. M. (1971) Protein and energy utilization by chicks fed graded levels of a balanced mixture of crystalline amino acids. J. Nutr. 101, 1249-1255. YOSHIDAA. A. E., HARPERt~; ELVEHJEMC. A. (1957) Effects of protein per calorie ratio and dietary level of fat on calorie and protein utilization. J. Nutr. 63, 555-570. Key Word Index--Protein; energy; amino acids; feed utilization; feed consumption; protein:calorie ratio; insect carcass composition: larval lipid;and larval nitrogen.
PROTEIN AND ENERGY UTILIZATION BY T H E INSECT, ARGYROTAENIA VELUTINANA (WALKER),* FED DIETS CONTAINING GRADED LEVELS OF AN AMINO ACID MIXTURE']" G. Y. Lu:~, J. D. GARLICH§AND G. C. RocK:~ Department of Entomology, North Carolina State University, Raleigh, NC 27607, U.S.A. (Received 19 October 1974) Abstract--l. Isocaloric diets containing graded levels of a balanced amino acid mixture (AAM) were fed to Argyrotaenia velutinana from the age of newly-hatched larvae to day 18. Feed consumption and larval weight gain increased with increasing amounts of AAM up to 3'6% of the diet. 2. The % of the ingested dietary nitrogen and energy recovered in the carcass at 18 days was highest for the larvae fed the diet containing 3.0% AAM. 3. Carcass composition increased in nitrogen and decreased in lipid with increasing dietary protein: calorie ratio. Carcass composition changes are similar to changes in another uricotelic organism, the birds.
INTRODUCTION NUTRITIONAL studies with homeotherms have shown that in general the dietary protein:calorie ratio influences feed consumption, growth rate, efficiency of energy and protein utilization, and carcass composition. Optimum protein:calorie ratios have been established experimentally for chicks (Donaldson et al., 1956; Velu et al., 1971), turkeys (Blixler et al., 1969) ducks (Scott et al., 1959), rats (Hegsted & Neff, 1970); Yoshida et al., 1957), pigs (Clawson et al., 1962), and lambs (Jones & Hogue, 1960). The work reported here contains the results of experiments designed to investigate the optimal level of dietary protein for the phytophagous insect Argyrotaenia velutinana (Walker). The larvae were fed isocaloric diets containing graded levels of a balanced amino acid mixture. Protein and energy consumption, utilization, growth rate, and carcass composition were determined.
amount of a heat sterilized diet. The larvae were reared xenically and antimicrobial agents were added to the diets. The larvae were allowed to feed and develop for 18 days. The insects were reared at 27 ___0"5°C with a 16hr illumination period/day.
MATERIALS AND METHODS Insect rearing The rearing techniques and methods for maintaining laboratory colonies and preparing chemically defined diets for A. velutinana were essentially the same as previously reported by Rock & King (1966, 1967). Egg masses were surface sterilized by immersion in a 10% formalin solution for 20min, and 5 newly-hatched larvae were transferred to a capped l oz plastic jelly cup containing a known * Lepidoptera: Tortricidae. t This investigation was supported in part by research grant AI-08633 from the National Institute of Allergy and Infectious Diseases, National Institutes of Health. Paper No. 4488 of the Journal Series of the North Carolina Agricultural Experiment Station, Raleigh, NC. :[:Department of Entomology. § Department of Poultry Science. 615
Table 1. Composition of the amino acid diet for A. velutinana at a 3% level of dietary protein Compoo£tion
S/IOOs dte¢ kmiuo 8 c l d
19 smlno a c l d s I ( L - a l l o f r e e )
3.000
Dmxcrox 2
5.000
Choleoterol
0 • 200
S a f f l o w e r o£1
0.300
Wesson u l t W 3
1.200
Z~'I2~uSO 4
0.005
,,*04,,%0
o.o~o
B-vttmain a/xture I
0.142
l ~ e e n 80
0.300
Ant:tmlcroblal a s e n t s 4
2 al
~r
3.00
2 M KOII to Sive pH 6.2 D i s t i l l e d wster Co 1(]08
~For composition, see Rock & King (1967a). 2 The purified amino acid mixture was added to or omitted from the diet at the expense of dextrose. 3 Osborne, T. B. & Mendel, L. B. (1932) A modification of the Osborne-Mendel salt mixture containing only inorganic constituents. Science, N.Y. 75, 339. 4Sorbic Acid, 20'0g; methyl parasept (methyl para-hydroxybenzoate), 15-0g; and ethyl alcohol, 170.0ml.
816
G . Y . L . , J. D. GARLICH AND G. C. ROCK
Diet composition The composition of the amino acid diet for rearing A. velutinana is shown in Table 1. The pattern of the amino acids in this dietary mixture was similar to the amino acid pattern found in the carcass of A. velutinana (Rock & King, 1966). Feeding tests with A. velutinana had shown that an amino acid mixture patterned after that found in the carcass would support optimum larval growth (Rock & King, 1967/)). The different amino acid mixtures were essentially isocaloric. Changes in the calorie:protein ratio were accomplished by altering the proportions of the amino acid mixtures and dextrose, while the level of other nutrients remained constant. The major dietary constituents were obtained from Nutritional Biochemicals Corporation, Cleveland, Ohio. Weight 9ain,food consumption, nitrogen and lipid percentage measurements All results were expressed on the dry weight basis. The dry weight was determined by drying 16 hr at 100°C. The dry weight of food introduced was calculated by using the mean ~o of dry matter from 5 aliquots which had been dried to a constant weight. At the end of the feeding period, the left-over food was separated from the feces and dried to a constant weight. The quantity of food eaten was calculated by subtracting the dry weight of uneaten food from the dry weight of the food originally introduced. The dry carcasses of the larvae were crushed into small pieces and were extracted with redistilled petroleum ether
in a soxhlet apparatus for at least 3 hr. The ether, containing the neutral lipids from the larvae, was transferred to tared vials and evaporated with nitrogen. The lipid was determined gravimetrically. Although this procedure does not remove phospholipid, it does estimate the lipid stored in fat bodies. The dry fat-free larval carcasses were transferred to a 30 ml Kjeldahl flask for nitrogen determination (McKenzie & Wallace, 1953). Carcass energy was calculated by usingthe method of Fraps & Carlyle (1939). Chitin was not included in this calculation. Dietary metabolizable energy was calculated by a method similar to that of Scott et al. (1969). Carcass protein was defined as N x 6.25. It is recognized however, that some of this nitrogen was present in the chitinous exosketon. Data are not corrected for sex differences since sex could not be determined at the time an experiment was completed. Each experiment had 4 replicates with 15-20 individuals/replicate. The results were analyzed statistically using analysis of variance (Steel & Torrie, 1960). Differences between individual treatment means were tested for significance by use of Duncan's Multiple F-Test (Duncan, 1955).
RESULTS Larval feed c o n s u m p t i o n a n d weight gain were m a x i m u m when the diet contained 3"6~o a m i n o acid mixture (Table 2). The efficiency of feed utilization (carcass dry weight gain: feed ratio) was at a maxi-
Table 2. Performance of A. velutinana fed diets containing graded levels of the amino acid mixture ~ ~ i u o Acid m:f~cure l e v e l X
Dry wc g a i n / l a r v a 2 ms
Feed c o n s ~ p t i n ~ / l a r v a mg
C~in/feed 2
2.4
0.81 a
4.11
3.0
1.S7 ab
6.31
0 . 2 0 ab
3.6
3.22 c
15.10
4.2
2.35 bc
10.31
0 . 2 3 be
4.8
1.6S ab
9.12
0 . 1 8 ab
5.4
2 , 2 1 bc
13.16
0.2S c 0 . 2 1 abe
0.17 a
All values are means of four replicate groups of 18-day old larvae. 2 Means followed by the same letter do not differ significantly (P < 0.05). Table 3. Protein and energy retention by A. velutinana fed diets containing graded levels of amino acid mixture ~ ~Lino a c i d mixture level Z
Consumption
Protein22 m8 x 10
ReCentlon in Carcase
Energy 3 calories
Protein 2 mg x 10 - 2
Energy 4 calorine
Effielency
5
P r o t e i n Energy Z
Z
2.4
75
13
35
4
47
31
3.0
142
19
77
8
54
42
3.6
406
46
141
16
35
35
4.2
317
30
116
12
37
40
4.8
318
26
89
8
28
31
5.4
501
27
118
11
24
41
Means of four replicate groups of eighteen-day old larvae. 2 Protein = N x 6"25. 3 Mg dextrose x 3"65 cal + m g lipid x 9.35 cal + mg amino acid x 3.65 cal (Scott et al., 1969). 4 Carcass energy = mg lipid x 9'35 cal + mg protein x 5'66 cal (Fraps & Carlyle, 1939), carbohydrate (chitin) was not included. 5 Percentage of ingested protein (N x 6"25) and energy recovered in the carcass of 18-day old larvae.
Utilization by insect fed amino acid mixture diets 2(;
) ';o 15
,,=, ,o ,,=, s
0/) 14.8
I I I I I0 20 30 40 ENERGY CONSUMPTION (Colories)
o
I 50
Fig. 1. The relationship between dietary energy consumption and energy recovered in the carcass of the 18-day old larva (A. uelutinana). The numbers in parenthesis beside the circles indicate the percentage of amino acid mixture in the diet. mum for the range of dietary amino acid levels between 3"0 and 4"2~ of the diet. The efficiencies of energy and protein (N x 6.25) utilization are shown in Table 3. A plot of energy recovered as fat and protein in the carcass at 18 days versus metabolizable energy consumed indicated a relationship described by the equation Y+ 0.373 + 0.352X where Y represents energy in the carcass and X represents energy consumed (Fig. 1). The good linear fit (r 2 = 0'93) indicates that over the range of amino acid intakes studied the utilization of energy for carcass deposition was rather constant. The slope of the line indicates that approximately 35~ of the ingested energy can be recovered as productive energy in the form of carcass fat and protein. A plot of protein consumed versus protein recovered in the carcass indicated a rather linear relationship for intake of the diets containing from 2"4 to 4-270 of the amino acid mixture (Fig. 2). At higher levels of dietary amino acid mixture reduced amounts of ingested protein were recovered in the carcass. Larval carcass composition changed in response to the dietary amino acid:calorie ratio (Table 4). Carcass
/
150
,~ 130 "~ ¢= IIC z
(4.2)~
/
50 Y = 22.00 + 0.298X
IO
I
I
I
L1pid 2
2.4
6.9 a
28.5 a
3.0
7.8 b
25.3 abc
3.6
7.0 a
26.8 ab
4.2
7.9 b
23.5 bed
4.8
8.6 b
20.3 d
5.4
8.6 b
2 0 . 8 cd
~All values are means of four replicate groups of eighteen-day old larvae. 2 Means followed by the same letter do not differ significantly (P < 0'05). 31 2$
o
27 '
0
0
23
y
21
0
J r
57
I 6
I I 7 8 NITROGEN, %
I 9
I I0
Fig. 3. The relationship between carcass lipid and nitrogen a s influenced by the dietary protein:calorie ratio. nitrogen increased and carcass lipid decreased with increasing dietary levels of amino acid mixture. A regression equation relating carcass nitrogen and lipid is shown in Fig. 3. Y = 57.96-4.33 X, where Y represents percent carcass lipid and X represents 70 carcass nitrogen. The goodness of linear fit is indicated by an r 2 = 0'956. DISCUSSION
(5 4 ) e
~ 7c
0
Larval composition as % of dry veisht
Nitrosen 2
3.61
014.81
9G
Table 4. The nitrogen and lipid composition of A. velutinana fed diets containing graded levels of amino acid mixture t Amino a c l d =£xl;ure l e v e l %
(4 2)0/
~
>-
617
I
I
o I00 200 300 400 500 PROTEIN CONSUMED(rag x I0 "z)
Fig. 2. The relationship between dietary protein consumed and protein recovered in the carcass of the 18-day old larva (A. velutinana). The numbers in parenthesis indicate the percentage of amino acid mixture in the diet. The equation for the line was calculated for the values represented by circles. The values represented by solid circles were not included in the calculation.
Velu et al. (1971) who studied young chickens stated that the optimum dietary requirement for protein (N x 6"25) from a balanced amino acid mixture must be defined in terms of a specific criterion or response. For" example, they observed that a 20% greater dietary protein content was required to maximize chick weight gain and protein retention and 60~ more to maximize gain:feed ratio and body protein concentration than was required to maximize feed and energy consumption or energy retention. Body fat was maximal at low levels of dietary protein. Also for pigs (Clawson et al., 1962) and rats (Yoshida et al., 1957) the dietary protein:calorie ratio was observed to influence feed consumption and body weight gain. Table 5 summarized the observations on A. oelutinana. In the present study larval feed intake and body weight gain were maximal when the diet contained 3"670 amino acid mixture. At greater levels of
6f8
G.Y. Lll, J. D. GARLICHAND G. C. ROCK Table 5. Response criteria as a function of dietary concentration of the amino acid mixture Criterion
Required amino acid m:txcure co~cengratio~
their response to altered dietary amino acid:calorie ratios. In particular, the carcass composition changes in the larvae are similar to the changes in another uricotelic organism, the birds.
Z Max-/.mal g a i n / f e e d r a t i o
3.0
Haximal veighc gain
3.6
~Y~t
3.6
protein r e t e n t i o n
Haxgmal energy r e t e n t i o n
3.6
14aximal food constBpCion
3.6
l~txi~utl emerg7 consumption
3.6
14ax£eud. body proCe:tn Z
4.8
Hini3um body Lipid Z
4.8
dietary amino acid mixture feed intake and weight gain declined. Velu et al. (1971) observed that the feed intake of chicks also declined when the diet contained high levels of a balanced amino acid mixture. The larvae of A. oelutinana demonstrated a rather constant rate of deposition of ingested energy in the carcass over the entire range of dietary amino acid levels (Fig. 1). This was true despite the differences in feed intake. Velu et al. (1971) reported a similar observation for chicks. Hegsted & Neff (1970) demonstrated that "protein utilization in young rats is constant over an appreciable range of intakes from the maintenance levels to those which allow near maximal growth." Velu et al. (1971) found this to hold true for chicks also. A similar response was obtained with A. oelutinana larvae as shown by the plot of carcass protein content versus protein intake (Fig. 2). A linear equation (r 2 = 0.961), Y = 22'0 + 0"298 X where Y represents carcass protein (N x 6.25) and X represents protein consumed describes amino acid utilization for dietary amino acid levels between 2.4 and 4.2~ of the diet. Within this range 29"8~o of the ingested nitrogen was recovered in the carcass at 18 days. At dietary amino acid levels of 4"8~o and above the efficiency of utilization was less. There was an inverse relationship between the nitrogen and lipid content of the carcass of A. velutinana (Fig. 3). As the nitrogen content of the insect larva increased I~o the lipid content decreased 4.33~. A similar relationship has been reported for the chick (Velu et al., 1971) and the rat (Bender & Miller, 1953). Velu et al. (1971) observed that maximal body protein ~ and minimal body fat occurred in chick which consumed diets containing greater amounts of protein than were required for maximal body weight gain. This was also true for A. velutinana. In chicks (Donaldson et al., 1956; Velu et al., 1971), turkeys (Donaldson et al., 1958) and ducks (Scott et al., 1959) carcass lipid content increased as the dietary protein: calorie ratio decreased. The larvae of A. velutinana exhibited a similar response (Table 4). The results of this study indicate a striking similarity in response between insect larva, A. oelutinana, and certain mammalian and avian species in
REFERENCES
BIXLER E. G., COMBSG. F. & SHAFFNERC. S, (1969) Effect of protein level on carcass composition of turkeys. Poult. Sci. 48, 261-266. BENDER A. E. & MILLER D. S. (1953) Constancy of the N/I-I20 ratios of the rat and its use in the determination of the net protein value. Biochem. J. 53, 7-8. CLAWSON A. J., BLUMER T. N., SMART W . W . G. & BARRICK E. R. (1962) Influence of energy-protein ratio on performance and carcass characteristics of swine. J. Anita. Sci. 21, 62-68. DONALDSON W . E., COMBS G . E. & ROMOSER G . L . (1956) The effect of calorie-protein ratio of the ration on growth, nutrient utilization, and body composition of chicks. Poult. Sci. 35, II00-1105. DONALDSON et al., (1958) Studies on energy levels in poultry rations. Effects of calorie-protein ratio of the ration on growth, nutrient utilization and body composition of poults, ibid 37, 614-619. DUNCAN D. B. (1955) Multiple range and multiple F-tests. Biometries II, 1-42. FRAPS G. S. & CARLYLE E. C. (1939) The utilization of the energy of feed by growing chicks. Tex. Agr. Exp. Sta. Bul. 571. HEGSTEO D. M. & NEFF R. (1970) Efficiency of protein utilization in young rats at various levels of intake. J. Nutr. 100, 1173-1179. JONES J. R. & HOOUE D. E. 0960) Effect of energy level on the protein requirement of lambs fattened with and without stilbestrol. J. Anita. Sci. 19, 1049-1054. MCKENZIE H. A. & WALLACEH. S. (1954) The Kjeldahl determination of nitrogen: A critical study of digestion condition-temperature, catalyst, and oxidizing agent. Aust. J. Chem. 7, 55-70. ROCK G. C. & KING K. W. (1966) Amino Acid composition in hydrolysates of the red-banded leaf roller, Argyrotaenia velutinana (Lepidoptera:Tortricidae) During development. Ann. ent. Soc. Am. 59, 273-275. ROCK G. C. & KING K. W. (1967) Qualitative amino acid requirements of the red-banded leaf roller, Argyrotaenia velutinana. J. Insect Physiol. 13, 59-65. ScoTr M. L., HILL F. W., PARSONS E. H. & BRUCKNER J. H. (1959) Studies on duck nutrition, No. 7. Effect of dietary energy:protein relationships upon growth, feed utilization, and carcass composition in market ducklings. Poult. Sci. 38, 497-507. SCOTT M. L., N~HEIM M. C. & YOUNG R. J. (1969) Nutrition of the chicken. M. L. Scott & Associates. Ithaca, New York. STEEL G. D. & TORRIE J. H. (1960) Principles and Procedures of Statistics. McGraw-Hill, New York. VELU J. G., BAKER D. H. & SCOTT H. M. (1971) Protein and energy utilization by chicks fed graded levels of a balanced mixture of crystalline amino acids. J. Nutr. 101, 1249-1255. YOSHIDAA. A. E., HARPERt~; ELVEHJEMC. A. (1957) Effects of protein per calorie ratio and dietary level of fat on calorie and protein utilization. J. Nutr. 63, 555-570. Key Word Index--Protein; energy; amino acids; feed utilization; feed consumption; protein:calorie ratio; insect carcass composition: larval lipid;and larval nitrogen.