6
Stability of crystalline and coated vitamins during manufacture and storage of fish feeds M. MARCHETTI & N. TOSSANI Vitamin Research Centre, Department of Biochemistry G. Moruzzi, University of Bologna, Bologna, Italy S. MARCHETTI Department of Veterinary Morphophysiology and Animal Production, University of Bologna, Bologna, Italy G. BAUCE Hendrix Research Centre, Mozzecane (VR), Italy Abstract The stability of two forms of vitamins, crystalline and fat- coated, during manufacturing processes and storage of fish feeds was investigated. After extrusion, vitamin recovery was generally lower than that found after pelleting. The recovery of coated forms after pelleting was higher than that of crystalline ones, especially for ascorbic acid, menadione, pyridoxine and folic acid. Coated forms were also found to be more resistant to extrusion than crystalline forms. No significant dierences in vitamin losses during storage were found between pelleted and extruded feeds. However, losses of ascorbic acid, menadione and pyridoxine in both manu- factured feeds were much greater in crystalline than in coated forms. KEY WORDS: KEY WORDS: extrusion, fish feed, pelleting, storage, vitamins Received 17 February 1998, accepted 25 November 1998 1 Correspondence: Prof. M. Marchetti, Department of Biochemistry G. Moruzzi, Via Irnerio, 48, 40126 Bologna, Italy 2 Introduction Vitamin supplementation of feeds is essential to ensure that farmed animals receive an adequate and balanced supply of these micronutrients to achieve optimal performance; in feed ingredients, vitamins occur in small and sometimes variable quantities. Particularly important is vitamin supplementation of aquaculture feeds, since the dietary vitamin requirements of fish, in general, and some other species in particular are much higher than those of other animals (Halver 1989; Woodward 1994; De Silva & Anderson 1995 3 ). However, proper integration is dicult to achieve owing to the great instability of many vitamins with physical and chemical agents. The presence of trace-minerals 4 and choline (March- etti et al. 1995b 5 ) and, above all, stress during manufacturing processes and storage cause serious losses of vitamin contents in feeds (Lovell 1989; Sandnes & Utne 1991; Gadient et al. 1992; McGinnis 1994; Gadient & Fenster 1994; Li et al. 1996). Although over 6 fortification of vitamins is often made to compensate for expected losses (Robison 1991), this practice does not always ensure that farmed animals receive adequate and balanced supplies of these micronutrients. We therefore carried out studies aimed at ascertaining whether the use of vitamins in forms unlike those normally used in feed supplements could reduce the processing and storage losses that occur to such a great extent in fish feeds. In a previous work, we studied the behaviour of the fat- soluble vitamins retinol, cholecalciferol and tocopherol coated with fat and compared it with that of commercial forms of the same vitamins in fish feeds during pelleting, extrusion and storage (Marchetti et al. unpubl. obs.). In the present study, we compared the stability of B-complex vitamins, ascorbic acid and menadione (as men- adione sodium bisulphite), in coated and crystalline forms during manufacturing processes and storage. Materials and Methods Chemicals All reagents were analytical grade; HPLC grade chemicals were used for liquid chromatography. Assay media supplied by Difco Laboratories (Detroit, MI, USA) and microorganisms supplied by American Type Culture Collec- tion (Rockville, MD, USA) were used in microbiological determinations. 115 Aquaculture Nutrition 1999 5 ; 115^120 . ............................................................................................. . ............................................................................................. Ó 1999 Blackwell Science Ltd

Stability of crystalline and coated vitamins during manufacture and storage of fish feeds

Embed Size (px)

Citation preview

Page 1: Stability of crystalline and coated vitamins during manufacture and storage of fish feeds

Stability of crystalline and coated vitamins duringmanufacture and storage of ®sh feeds

M. MARCHETTI & N. TOSSANI Vitamin Research Centre, Department of Biochemistry G. Moruzzi, University

of Bologna, Bologna, Italy

S. MARCHETTI Department of Veterinary Morphophysiology and Animal Production, University of Bologna, Bologna,

Italy

G. BAUCE Hendrix Research Centre, Mozzecane (VR), Italy

Abstract

The stability of two forms of vitamins, crystalline and fat-

coated, during manufacturing processes and storage of ®sh

feeds was investigated. After extrusion, vitamin recovery was

generally lower than that found after pelleting. The recovery

of coated forms after pelleting was higher than that of

crystalline ones, especially for ascorbic acid, menadione,

pyridoxine and folic acid. Coated forms were also found to

be more resistant to extrusion than crystalline forms. No

signi®cant di�erences in vitamin losses during storage were

found between pelleted and extruded feeds. However, losses

of ascorbic acid, menadione and pyridoxine in both manu-

factured feeds were much greater in crystalline than in coated

forms.

KEY WORDS:KEY WORDS: extrusion, ®sh feed, pelleting, storage, vitamins

Received 17 February 1998, accepted 25 November 19981

Correspondence: Prof. M. Marchetti, Department of Biochemistry

G. Moruzzi, Via Irnerio, 48, 40126 Bologna, Italy2

Introduction

Vitamin supplementation of feeds is essential to ensure that

farmed animals receive an adequate and balanced supply of

these micronutrients to achieve optimal performance; in feed

ingredients, vitamins occur in small and sometimes variable

quantities. Particularly important is vitamin supplementation

of aquaculture feeds, since the dietary vitamin requirements

of ®sh, in general, and some other species in particular are

much higher than those of other animals (Halver 1989;

Woodward 1994; De Silva & Anderson 19953 ). However,

proper integration is di�cult to achieve owing to the great

instability of many vitamins with physical and chemical

agents. The presence of trace-minerals4 and choline (March-

etti et al. 1995b5 ) and, above all, stress during manufacturing

processes and storage cause serious losses of vitamin contents

in feeds (Lovell 1989; Sandnes & Utne 1991; Gadient et al.

1992; McGinnis 1994; Gadient & Fenster 1994; Li et al.

1996).

Although over6 forti®cation of vitamins is often made to

compensate for expected losses (Robison 1991), this practice

does not always ensure that farmed animals receive adequate

and balanced supplies of these micronutrients.

We therefore carried out studies aimed at ascertaining

whether the use of vitamins in forms unlike those normally

used in feed supplements could reduce the processing and

storage losses that occur to such a great extent in ®sh feeds.

In a previous work, we studied the behaviour of the fat-

soluble vitamins retinol, cholecalciferol and tocopherol

coated with fat and compared it with that of commercial

forms of the same vitamins in ®sh feeds during pelleting,

extrusion and storage (Marchetti et al. unpubl. obs.).

In the present study, we compared the stability of

B-complex vitamins, ascorbic acid and menadione (as men-

adione sodium bisulphite), in coated and crystalline forms

during manufacturing processes and storage.

Materials and Methods

Chemicals

All reagents were analytical grade; HPLC grade chemicals

were used for liquid chromatography. Assay media

supplied by Difco Laboratories (Detroit, MI, USA) and

microorganisms supplied by American Type Culture Collec-

tion (Rockville, MD, USA) were used in microbiological

determinations.

115

Aquaculture Nutrition 1999 5;115^120. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ó 1999 Blackwell Science Ltd

Page 2: Stability of crystalline and coated vitamins during manufacture and storage of fish feeds

Crystalline vitamins to be incorporated into feeds were

purchased from Ho�man-La Roche, Basle, Switzerland and

coated vitamins from Trouw Nutrition-Nutreco, Verona,

Italy.

Feeds

Two commercial ®sh feeds (produced by Hendrix, Mozze-

cane, Verona, Italy) with the same composition (Table 1)

were used in the study. One was forti®ed with crystalline

vitamins, the other with vitamins coated with fat (for fatty

acid composition, see Table 2). Both feeds were processed by

either extrusion or pelleting. Processing parameters used to

produce the pellets and physical characteristics of experi-

mental feeds are given in Table 3.

Analytical methods

The feeds were analysed for their vitamin contents before and

after two processes by the following methods: thiamin and

Table 1 Ingredients and proximate composition of experimental feed

Ingredient g kg)1

Bloodmeal 50Choline chloride (50%) 15Dried whey 50Fish meal 420Fish oil 150Magnesium sulphate 3Meat meal 50Mineral premix1 10Sodium chloride 4Soy lecithin 13Soybeanmeal 160Vitamin premix2 10Wheat starch 80

Approximate composition

Dry matter 891

On dry matter basis28 :Ash 102Fibre 11Lipid 210Protein 510

1 The mineral premix provides the following mg kg)1 of feed: ironsulphate (FeSO4.7H2O),150; zinc sulphate (ZnSO4.7H2O), 240; manganesesulphate (MnSO4.4H2O), 180; copper sulphate (CuSO4. 5H2O), 25; cobaltsulphate (CoSO4.7H2O), 18; calcium iodate (CaIO3.6H2O), 12; sodiumselenite (Na2S2O4), 2.3.2 The vitamin premix provides the following mg kg)1 of feed: retinylpalmitate (500.000 IU g)1), 40; DLDL-cholecalciferol (100.000 IU g)1), 10; DLDL-a-tocopheryl acetate (50%),120; menadione sodium bisulphite (MSB), 60;thiamin hydrochloride, 30; ribo£avin, 40; pyridoxine hydrochloride, 80;nicotinamide, 400; ascorbic acid, 200; DD-calcium pantothenate (91%),250; folic acid (90%), 7.5; DD-biotin (2%), 7.5; cyanocobalamin (1& ), 300.

Table 2 Fatty acid composition and chemical-physical characteris-

tics of fat used for vitamin coating

Fatty acid

8:0^12:0 < 1 %14:0 2^3 %16:0 28^30 %18:0 60^66 %18:1 0.5^1 %Iodine number (g I100 g)1) < 1Acidity number (mg KOH g)1) < 8Saponification number (mg KOH g)1) 190^198Melting point (C°) 62^65

Table 3 Processing parameters and physical characteristics of

experimental feeds

Extrusion Pelleting

Parameters

Machine type Wenger X/185 CPM 7000Added water and steam (%) 16 5Pressure (bar) 12 2.5Conditioning time (s) 25 10Temperature at intake (°C) 85 55Temperature at outlet (°C) 96 68Drying temperature (°C) 95 öDrying time (min) 20 öTemperature at outlet of dryer (°C) 48 öPhysical characteristics

Diameter (mm) 5.0 4.8Bulk density (kg L)1) 0.54 0.68Moisture content (g kg)1) 8 9Moisture content after30 min leaching (g kg)1) 26 18

Table 429,30: Levels of vitamins in crystalline form after manufacturing

process of feed

Feed vitamin content (mg kg)1)

Vitamin Before After pelleting After extrusion

Ascorbic acid 207 þ 16a 107 þ 12b 40.8 þ 5.4c

Biotin 1.47 þ 0.2 1.39 þ 0.2 1.38 þ 0.2Cyanocobalamin 0.26 þ 0.03 0.23 þ 0.04 0.22 þ 0.04Folic acid 6.36 þ 0.8a 4.05 þ 0.4b 3.05 þ 0.5b

Menadione 31.6 þ 3.6a 16.1 þ 3.1b 10.9 þ 2.2c

Nicotinamide 396 þ 35 380 þ 42 364 þ 44Pantothenic acid 226 þ 21 201 þ 19 194 þ 18Pyridoxine 79.7 þ 5.6a 60.2 þ 7.9b 53.0 þ 6.2b

Riboflavin 38.7 þ 4.5 33.8 þ 4.6 33.3 þ 5.6Thiamin 32.2 þ 2.5 26.3 þ 2.9 28.3 þ 3.5

Values are given as means (SEM) of results of assays carried out on threereplicate feed preparations. Means within a row with differentsuperscript letters are significantly different (P < 0.05).

M. Marchetti et al.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ó 1999 Blackwell Science Ltd Aquaculture Nutrition 5;115^120

116

Page 3: Stability of crystalline and coated vitamins during manufacture and storage of fish feeds

ribo¯avin by ¯uorimetric methods (AOAC 1995);

ascorbic acid (Ho�man et al. 1992) and menadione (La�

et al. 19887 ) by liquid chromatography. Other vitamins were

assayed by microbiological methods (AOAC 1995) using the

following test microorganisms: Saccharomyces8,9 uvarum 9080

for pyridoxine; Lactobacillus casei8,9 7469 for folic acid;

Lactobacillus10 plantarum 8014 for nicotinamide, pantothenic

acid and biotin; and Lactobacillus11 leichmanni 7830 for

cyanocobalamin.

Vitamin assays were repeated in feeds, stored in paper bags

at room temperature, 30, 90 and 180 days after manufacture.

Experiments were carried out on three replicates of feeds. On

every sample analyses were carried out in duplicate or

triplicate.

Statistical analysis

All the results were processed by analysis of variance (ANOVAANOVA)

using the general linear procedure of SPSS/PC (1988).

Di�erences were considered signi®cant when P < 0.05.

Results and Discussion

The results of vitamin assays in two types of feeds before and

after manufacturing processes (Tables 4, 5)12 show that vita-

min losses caused by the two processes were generally similar,

except for ascorbic acid and menadione, for which losses

caused by extrusion were greater than those caused by

pelleting (P < 0.05). Folic acid and pyridoxine levels also

su�ered to a greater extent than the others in both processes.13

However, the extent of the losses of these four most

vulnerable vitamins (ascorbic acid, menadione, folic acid and

pyridoxine) caused by the two processes di�ers according to

the form used: losses from coated forms were signi®cantly

lower than those from crystalline ones (ascorbic acid and

menadione P < 0.01, folic acid and pyridoxine P < 0.05,

respectively).

The results of vitamin assays in processed feeds stored for

various periods of times (Tables 6, 7, 8, 914 ) show no

signi®cant di�erences between vitamin losses from extruded

and pelleted feeds. Losses were of the same magnitude as

those observed in meal feeds not subjected to extrusion or

pelleting processes (Marchetti et al. unpubl. obs.).

Signi®cant di�erences were found between losses of

crystalline and coated vitamins for ascorbic acid, menadione

and, only in extruded feed, for pyridoxine in both types of

manufactured feed. When used in a coated form, after

180 days of storage these vitamins su�ered signi®cantly

lower losses than those in crystalline form (in pelleted feed:

Table 531,32: Levels of vitamins in coated form after manufacturing

process of feed

Feed vitamin content (mg kg)1)

Vitamin Before After pelleting After extrusion

Ascorbic acid 191 þ 14a 166 þ 20a 100 þ 14b

Biotin 1.67 þ 0.2 1.62 þ 0.3 1.64 þ 0.3Cyanocobalamin 0.27 þ 0.03 0.25 þ 0.03 0.25 þ 0.03Folic acid 6.18 þ 0.8 5.81 þ 0.6 5.56 þ 0.7Menadione 32.3 þ 4.1a 28.1 þ 3.1a 21.8 þ 3.3b

Nicotinamide 424 þ 43 403 þ 52 399 þ 50Pantothenic acid 236 þ 20 222 þ 26 215 þ 24Pyridoxine 76.6 þ 6.9 72.9 þ 7.8 69.9 þ 6.2Riboflavin 38.5 þ 3.3 37.3 þ 5.2 36.2 þ 4.8Thiamin 28.4 þ 2.5 27.0 þ 3.9 25.6 þ 3.5

Values are given as means (SEM) of results of assays carried out on threereplicate feed preparations. Means within a row with differentsuperscript letters are significantly different (P < 0.05).

Table 6 Levels33 of vitamins in crystalline form after storage of

pelleted feed

Feed vitamin content (mg kg)1) at time

Vitamin 0 days 30 days 90 days 180 days

Ascorbic acid 112 þ 13a 83.0 þ 9.6a 48.9 þ 7.6b 24.7 þ 1.9c

Biotin 1.53 þ 0.2 1.50 þ 0.2 1.46 þ 0.2 1.36 þ 0.3Cyanocobalamin 0.29 þ 0.03 0.27 þ 0.04 0.24 þ 0.04 0.22 þ 0.03Folic acid 4.76 þ 0.4 4.56 þ 0.6 4.26 þ 0.5 3.94 þ 3.8Menadione 21.8 þ 2.1a 18.6 þ 2.7a 15.0 þ 2.3b 9.17 þ 1.5c

Nicotinamide 410 þ 37 403 þ 37 395 þ 35 378 þ 37Pantothenic acid 205 þ 18 194 þ 23 174 þ 23 150 þ 21Pyridoxine 65.6 þ 5.0a 60.6 þ 4.8a 52.1 þ 7.2a 46.3 þ 5.4b

Riboflavin 33.5 þ 3.3 32.4 þ 2.8 31.9 þ 3.4 29.8 þ 4.0Thiamin 26.2 þ 3.9 25.4 þ 3.7 26.9 þ 2.7 23.1 þ 2.7

Values are given as means (SEM) of results of assays carried out on threereplicate feed preparations. Means within a row with differentsuperscript letters are significantly different (P < 0.05).

Table 7 Levels34 of vitamins in coated form during storage of pelleted

feed

Feed vitamin content (mg kg)1) at time

Vitamin 0 days 30 days 90 days 180 days

Ascorbic acid 161 þ 15a 153 þ 18a 133 þ 15a 122 þ 13b

Biotin 1.62 þ 0.2 1.62 þ 0.2 1.57 þ 0.2 1.51 þ 0.2Cyanocobalamin 0.24 þ 0.04 0.24 þ 0.03 0.23 þ 0.04 0.20 þ 0.04Folic acid 5.83 þ 0.5 5.74 þ 0.7 5.60 þ 0.6 5.48 þ 0.5Menadione 30.2 þ 2.8 28.1 þ 3.6 26.2 þ 2.9 24.2 þ 3.5Nicotinamide 404 þ 38 402 þ 34 398 þ 36 385 þ 44Pantothenic acid 223 þ 20 215 þ 20 207 þ 21 198 þ 18Pyridoxine 70.3 þ 6.2 68.2 þ 5.2 64.3 þ 6.0 62.1 þ 6.8Riboflavin 37.4 þ 4.3 36.7 þ 4.2 36.1 þ 4.3 35.3 þ 4.3Thiamin 27.1 þ 2.4 26.9 þ 3.2 26.5 þ 3.5 25.5 þ 3.2

Values are given as means (SEM) of results of assays carried out on threereplicate feed preparations. Means within a row with differentsuperscript letters are significantly different (P < 0.05).

Vitamin stability in fish feeds

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ó 1999 Blackwell Science Ltd Aquaculture Nutrition 5;115^120

117

Page 4: Stability of crystalline and coated vitamins during manufacture and storage of fish feeds

ascorbic acid P < 0.01, menadione P < 0.05; in extruded

feed: ascorbic acid P < 0.01, menadione and pyridoxine

P < 0.05).

The data obtained in this study agree with the observations

of some authors (Lovell 1989; Sandnes & Utne 199115 ; Gadient

& Fenster 199416 ; Li et al. 1996) on the decay of some water-

soluble vitamins during manufacturing processes and storage

of ®sh feeds. However, our results clearly show the greater

stability of coated vitamins compared to crystalline ones

which are generally more vulnerable to attack by chemical

and physical agents.17

During feed manufacture, the recovery rates of ascorbic

acid, menadione, pyridoxine and folic acid in crystalline form

after pelleting were 52%, 51%, 76% and 64%, respectively,

whereas those in coated form were 87%, 87%, 95% and 94%

(Fig. 1). After extrusion, the recovery rates of the same

vitamins in crystalline form were 20%, 34%, 70% and 61%,

and in coated form 53%, 67%, 91% and 90%, respectively

(Fig. 2).

Our data con®rm previous ®ndings on premix vitamin

stability during the storage (Marchetti et al. 1995a18 ). In

pelleted feed, after 180 days of storage, only 30% of ascorbic

Table 8 Levels35 of vitamins in crystalline form during storage of

extruded feed

Feed vitamin content (mg kg)1) at time

Vitamin 0 days 30 days 90 days 180 days

Ascorbic acid 48.4 þ 4.5a 36.1 þ 3.5a 16.7 þ 1.5b 9.72 þ 1.0c

Biotin 1.34 þ 0.2 1.28 þ 0.1 1.27 þ 0.1 1.22 þ 0.2Cyanocobalamin 0.22 þ 0.04 0.20 þ 0.02 0.17 þ 0.02 0.14 þ 0.03Folic acid 4.38 þ 0.4 3.70 þ 0.4 3.07 þ 0.4 2.95 þ 0.4Menadione 12.9 þ 2.2a 10.6 þ 0.9a 8.04 þ 1.1b 5.16 þ 0.8c

Nicotinamide 392 þ 41 388 þ 42 387 þ 43 380 þ 44Pantothenic acid 194 þ 17 171 þ 20 152 þ 18 142 þ 17Pyridoxine 61.8 þ 5.5a 56.2 þ 5.1a 47.9 þ 4.1a 38.0 þ 3.8b

Riboflavin 35.5 þ 3.7 35.0 þ 3.9 33.2 þ 4.1 29.6 þ 3.9Thiamin 30.1 þ 2.6 29.3 þ 2.4 25.4 þ 1.9 23.8 þ 2.8

Values are given as means (SEM) of results of assays carried out on threereplicate feed preparations. Means within a row with differentsuperscript letters are significantly different (P < 0.05).

Figure 1 Levels of vitamins retained in crystalline and coated forms

in feed after pelleting process. Data, expressed as percentage of

vitamin retained, are given as mean (SEM) of results of assays

carried out on three replicate feed preparations. Signi®cant

di�erences between two vitamin forms are indicated by asterisks

(*P < 0.05; ** P < 0.01).

Figure 2 Levels of vitamins retained in crystalline and coated forms

in feed after extrusion process. Data, expressed as percentage of

retained vitamin, are given as means (SEM) of results of assays

carried out on three replicate feed preparations. Signi®cant di�eren-

ces between two vitamin forms are indicated by asterisks (* P < 0.05;

** P < 0.01).

Table 9 Levels of vitamins in coated form during storage of extruded

feed

Feed vitamin content (mg kg)1) at time

Vitamin 0 days 30 days 90 days 180 days

Ascorbic acid 89.5 þ 8.01a 85.9 þ 8.25a 77.0 þ 9.27a 71.7 þ 8.46b

Biotin 1.73 þ 0.20 1.66 þ 0.18 1.60 þ 0.19 1.60 þ 0.20Cyanocobalamine 0.29 þ 0.03 0.28 þ 0.03 0.24 þ 0.03 0.22 þ 0.04Folic acid 5.74 þ 0.55 5.42 þ 0.60 5.20 þ 4.89 4.96 þ 0.62Menadione 19.0 þ 2.18a 18.0 þ 2.16a 15.9 þ 2.02a 14.6 þ 2.12b

Nicotinamide 406 þ 37.3 400 þ 36.9 400 þ 43.9 394 þ 43.2Pantothenic acid 205 þ 20.1 198 þ 21.6 194 þ 18.7 190 þ 21.1Pyridoxine 68.1 þ 5.96 67.3 þ 5.88 65.7 þ 5.54 62.9 þ 7.46Riboflavin 38.1 þ 4.21 37.6 þ 4.21 35.9 þ 4.12 34.3 þ 4.25Thiamin 26.2 þ 2.08 25.6 þ 2.36 24.8 þ 2.97 24.4 þ 2.96

Values are given as means (SEM) of results of assays carried out on threereplicate feed preparations. Means within a row with differentsuperscript letters are significantly different (P < 0.05).

M. Marchetti et al.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ó 1999 Blackwell Science Ltd Aquaculture Nutrition 5;115^120

118

Page 5: Stability of crystalline and coated vitamins during manufacture and storage of fish feeds

acid and 42% of menadione in crystalline form were found

whereas 76% and 86% were found in the coated form

(Fig. 3). In extruded feed, the quantities found after 180 days

were 20% for ascorbic acid, 40% for menadione and 66% for

pyridoxine in the crystalline form, and 70%, 76% and 92%,

respectively, in the coated form (Fig. 4).

These results show the bene®ts of using coated forms for

vitamin supplementation of feeds in general, but particularly

in aquaculture feeds which cannot be given in meal and

which are processed by pelleting or extrusion.

A further advantage of using coated forms of water-

soluble vitamins in ®sh feed supplementation is their lower

propensity for leaching compared with crystalline forms once

the feed has been immersed in water. Signi®cant di�erences

between the two vitamin forms were observed in both

manufactured feeds for all vitamins but particularly for folic

acid, pantothenic acid, ascorbic acid and menadione (Mar-

chetti et al. 1999).

These two characteristics of coated vitamins Ð greater

stability and lower leaching Ð mean that they may be used

to ensure that farmed ®sh receive better and more19 balanced

supplies of these important micronutrients, for optimal

performance.

Although the cost of coated vitamins is 10±15% higher

than that of ordinary commercial forms, they may prove to

be more economic, since the extra vitamin normally added in

manufacturing ®sh feed, in an attempt to compensate for

losses caused by manufacturing stress, storage and leaching,

may be reduced by at last 60%.

References

AOAC (1995) O�cial Methods of Analysis (Cunni�, P. ed.), 16th

edn. Association of O�cial Analytical Chemists, Washington,

DC.

De Silva, S.S. & Anderson, T.A. (1995) Fish Nutrition in Aquaculture,

pp. 87±93. Chapman & Hall, London, UK.

Gadient, M. & Fenster, R. (1994) Stability of ascorbic acid and other

vitamins in extruded ®sh feeds. Aquaculture, 124, 207±211.

Gadient, M., Fenster, R. & Latscha, T. (1992) Vitamin stability in

aquaculture feeds. Fish Farmer, Jan./Feb., 27±28.

Halver, J.E. (1989) The Vitamins. In: Fish Nutrition (Halver, J.E.

ed.), 2nd edn., Vol. 1, pp. 31±109. Academic Press Inc., San Diego,

CA.

Ho�man, K.M., Brown, P.R. & Maugle, P.D. (1992) Comparison of

three HPLC methods for the analysis of vitamers20 of ascorbic acid.

J. Liq. Chromatog., 15, 2581±2610.

La�, R., Marchetti, S. & Marchetti, M. (1988) Normal phase liquid

chromatographic determination of menadione in animal feed.

J. Assoc. O�. Anal. Chem., 71, 826±828.

Li, M.H., Rushing, J.B. & Robison, E.H. (1996) Stability of B-

complex vitamins in extruded cat®sh feeds. J. Appl. Aquacult., 6,

67±71.

Lovell, T. (1989) Nutrition and Feeding of Fish, pp. 108±113. Van

Nostrand Reinhold, Inc., New York, NY.

Marchetti, M., Tossani, N. & Marchetti, S. (1995a)21 Utilization of

microincapsulate forms of vitamin B1, C and K3 in premix

manufacture. Zoot. Nutr. Anim., 21, 25±33.22

Marchetti, M., Tossani, N. & Marchetti, S. (1995b)23 Vitamin

degradation in premix as a function of the kind of trace-mineral

present. Zoot. Nutr. Anim., 21, 67±73.24

Figure 3 Levels of vitamins retained in crystalline and coated forms

in pelleted feed after 180 days' storage. Data, expressed as percent-

age of retained vitamin, are given as means (SEM) of results of

assays carried out on three replicate feed preparations. Signi®cant

di�erences between two vitamin forms are indicated by asterisks

(* P < 0.05; ** P < 0.01).

Figure 4 Levels of vitamins retained in crystalline and coated forms

in extruded feed after 180 days' storage. Data, expressed as percent-

age of retained vitamin, are given as means (SEM) of results of assays

carried out on three replicate feed preparations. Signi®cant di�eren-

ces between two vitamin forms are indicated by asterisks (* P < 0.05;

** P < 0.01).

Vitamin stability in fish feeds

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ó 1999 Blackwell Science Ltd Aquaculture Nutrition 5;115^120

119

Page 6: Stability of crystalline and coated vitamins during manufacture and storage of fish feeds

Marchetti, M., Tossani, N., Marchetti, S. & Bauce, G. (1999)

Leaching of crystalline and coated vitamins in pelleted and

extruded feeds. Aquaculture, 171, 83±91.25

McGinnis, C.H. (1994) Maintaining vitamin stability during extru-

sion. Feed Mix, 2(2), 10±13.

Robison, E.H. (1991) A practical guide to nutrition fed, and feeding

of cat®sh. MI Agric. For. Exp. Stn Bull. No. 979.26

Sandnes, K. & Utne, F. (1991) Processing loss and storage stability of

ascorbic acid in dry ®sh feed. Fiskeridir. Skr. Ser. Ernaer., 2, 39±44.

SPSS Inc. (1988) SPSS/PC+ V2.0 Base Manual. SPSS Inc.,

Chicago, IL.

Woodward, B. (1994) Dietary vitamin requirements of cultured

young ®sh, with emphasis on quantitative estimates for salmonids27 .

Aquaculture, 124, 133±168.

M.Marchetti et al.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ó 1999 Blackwell Science Ltd Aquaculture Nutrition 5;115^120

120