Aspects of dietary protein quality for the growing pig

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ASPECTS OF DIETARY PROTEIN QUALITY FOR THE GROWIN G PIG

A thesis presented in partial fulfilment of the requirements for the degree of -

Doctor of Philosophy in Animal Science at Massey University

PAUL JM1ES NOUGHAN 1 984

MRSSEY UNIVERSITY

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1061259505

ABSTRACT

A st udy o f s everal aspec ts o f dietary prot ein qual ity for the growing pig is described . The s tudy was conducted in·three parts .

i i

Res ervat ions regard ing t h e int erpretat ion o f three recent empirical es t imates o f the ideal amino acid balance for the growing pig prompt ed the first part of the s t udy . A diet ( basal d i et ) was formulated in which enzyma t i cally hydrolysed case in s upplemented with synthet ic amino acids formed the sole prote in source . The balance of essential amino acids in the diet approximated the mean o f the three publ i shed es t imat es.

Eight en t ire male pigs ( boars ) o f 28 Kg init ial l iveweight , con­

f ined in me tabolism crat es , were f ed the basal diet for 20 days and thereafter a protein-f ree diet for a f urther e ight days . Mean daily exc ret ion of urinary urea nit rogen over s ix-day collect ion periods was 9 3 mg/Kg0 " 7 5 for p igs f ed the b asal diet and the corresponding value for the prot ein- f ree diet was ¹⁹ mg/Kg 0 " 7 5 • Assuming that the d i f f er­

ence between these values was attributable to deaminat ion of amino acids f rom the b asal die t , this corresponds to an e f f ici ency of util isat ion of dietary prot ein o f 0 . 940. It was concluded that the amino acid pat tern of the bas al diet approximated an ideal b alance .

Part two of the study entail ed the det ermination and evaluat ion o f es t imates of t h e apparent ileal diges t ib il ity o f crude pro tein and amino acids for the growing p ig and included a ccmparison of prot ein diges t ibi lity in the rat and p i g .

Samples o f ileal digesta were collected f rom boars prepared with T-piece cannulae in the terminal ileum. Values for the d iges t ib i l ity of crude_prot ein and amino acids in barley-meal , pea-meal , meat-and­

bone-meal , f i s h-meal and a mixture of enzyrnat i cally hydrolysed cas ein and synthet i c amino acids a re cited .

In an evaluation o f the det ermined d igest ib i l ity values t en b oars received a b arley- , pea- , meat-and-bone- , f ish-meal d i et and ten a con t rol diet containing enzyma t ically hydrolysed case in and syn thetic amino acids a s i ts sole protein source. The gro s s amino acid compos it ion

o f the latter diet equalled the det ermined apparent ileal digest ible amino acid compos i t ion of the barley-based diet . Accept ing that the cont rol protein source was compl et ely d igest ible and that the two feeding regimes we re iso- calori c , the s imilar growth characterist i cs of pigs on the two diets suggested that apparent ileal amino acid diges tibility coef f i ci ents are accurat e measures o f the degree o f amino acid diges tion and absorpt ion in the growing pig .

P reliminary results showed close agreement b etween the rat and pig for the apparen t i leal d iges t ibility of crude protein in barley- , meat-and-bone- and f ish-meal .

In the third part o f the study a det erministic comput er model which s imulates the d iges t ion and met abolism of d ietary nitrogen in the growing pig was constructed. The model was based on the concept of a part it ioning of daily dietary nit rogen intake in pig growth . Ini t ial val idation exercises demonstrated that results obtained f rom s imulation were in close agreement with obse rvat ions f rom experimen­

tat ion with the l ive animal.

i i]

iv ACKNO\.JLEDGEMENTS

S incere apprec iat ion is expressed to my supervisors , Dr. W. C. ·Smi th an d Prof essor D. S. Flux for their guidance and encouragemen t throughout the study. Spec ial thanks are ext ended to Pro f essor R. J. Townsley for his assis tance .

I would also like to thank :

Miss G. Borrie , Mr . M . T . Fisher , Dr . G . G . Midw inter , Mrs . Y . F . Moore

and Mrs. J. A. Rumb al for their ass i s t ance with ch emical analyses.

Mr . W. B . Parl ane and Mr . G. Pearson for technical as s istance.

Dr. D. W. Del low and Mr . A. S . D . King for the anima l surgery .

Mr. K. Best and Pr . G. Hanley for the care of animals on experiment .

Mr. D. J. Garrick for his advice on s ta t i s t ical mat t ers .

Hr. C. J . Harri s for assistance wi th t he comput er progranuning of the s imulat ion model .

Dr. K . A. C. James for ffiaking availab l e the data on the diges­

t ib i l i ty of dietary proteins by the rat.

Mrs . E. J . Baxter for her care and at tent ion in typing t his manuscrip t .

I ackno�ledge w i th gra t i t ude the generous financ ial assis tance of : Hel labys Lt d . ; The Massey University Agr icultural Research Founda tion;

May and Baker , N . Z . L t d . ; The New Zealand Pork Industry Board; Northern Rol ler Mi lls Feeds Ltd . ; Pf izer Laboratories N . Z. Lt d . ; The Tauranga Egg Market ing Cooperat ive Ltd.

I was the grat e f ul recipient o f a Univer s ity Grant s Commit t ee Post­

Graduate Scholarship , a Helen E. Akers S cholar�hip and a Johannes August Anderson Scholarship .

Fondes t appreciation i s expressed to my wif e , Meredi t h , for h er s upport and encouragement dur ing the conduct o f this s t udy .

P ART I.

TAB LE OF CONTENTS

AB STRACT

ACKNOWLEDGEMENTS LIST OF TABLES I NTRODUCTI ON

ESTABL I SHMENT OF THE I DEAL AHINO ACI D BALAN CE FOR G ROWTH IN THE P I G

Chap t er 1. Review o f Li te ra t u re

I . 1.1 I n t ro d u c t ion

I. 1. 2 The d e t e rmination o f amino a cid requiremen ts I. 1.3 I d eal amino a c i d b a l ance

I . 1. 4

I . 1. 5 I . 1. 6

I . 1. 7

I. 1. 8 I. 1. 9

Appro aches to the es timat ion of t h e ideal amino a cid b a l an ce

Est ima t e s o f the i d eal amino a cid b a l ance The i n f l uen ce o f d i e tary energy in take on t h e u t i l i sation o f d i e t ary amino acids

The in f l u ence of d i e tary e l e c t ro l y t es on t h e u t i lisa tion o f dietary amino acids

Deviation f rom an ideal am ino acid balanc e Con c l u sion

Chap t e r 2 . The As s e s smen t of a Balance o f Amino Acids Con­

s id e re d to be I deal for the G rowing P ig ( 20 t o

80 Kg Livewe ight) I . 2. 1

I . 2 . 2 I . 2. 3

I n t ro d u c t ion

Aspe c t s o f e xperimental des ign

P r e l iminary s t u dy one : The inf l uence of t h e

+ +

diet a ry (Na + K - Cl ) factor on the energy and nit rogen metab o l ism of the growing pig

(i) I n t ro d u c tion

(ii) Exper imen t a l p rocedure ( i i i ) Res u l t s

( iv) Dis cuss ion

Page

i i

iv ix

3

4 4 4 7

8 9

13

14

1 7 18

20 20 2 1

32 32 33 36 3 8

I. 2 . 4

I . 2 . 5

I . 2 . 6

I . 2 . 7

PART I I .

Chapter 1 . II . l. l

II . l . 2 I I . 1. 3

I I . 1. 4

I I . 1. 5

Prel iminary study two : The inf l uence of the pro tein- f ree ene rgy level of the basal diet on urinary urea exc ret ion in the growing pig ( i )

( i i ) ( i ii) ( iv)

Int roduct ion

ExpEriment al procedure Resul t s

Discussion

Pilot tr ia l : The est imat ion of the urinary total nit rogen excret ion of growing pigs fed the basal diet

( i ) ( i i ) ( i i i ) ( i v)

Int roduct ion

Experimental procedure Results

Discus s ion

Main s tudy : Determinat ion o f the irredu c ib l e minimum urinary urea nitrogen l o s s o f the gro"'ing pig

( i) ( ii) ( i ii) ( iv)

I n t roduct ion

Experimental procedure Resu l t s

Dis cuss ion Concluding dis cuss ion

THE DI GESTIBILITY OF ��1INO ACIDS IN PROTEINS FED TO THE GROWING PIG

Review o f Literature Int roduc tion

The diges t ion and absorpt ion o f prot ein The measurement of prot ein diges t ib i l i t y Ileal analys i s a s a meas ure o f amino acid diges tibility

Conclus ion

Page

40 40 40 42 42

4 4 4 4 44 4 4 45

4 7 4 7 4 8 50 52 56

6 1

6 2 62 62 65

70 72

Chapter 2. The Det e rminat ion and Assessment of Appa rent I l eal Diges t ib i l it y Coeffi cien t s fo r Crude Pro t e in and Amino Ac i d s in some Foods t uffs for the Growing

I I . 2. 1 I I . 2 . 2

Pig ( 2 0 t o 80 Kg Livewe ight ) Int roduct ion

De terminat ion of the digestibi l i t y of d i e t ary crude pro t ein and amino a c i ds in pro t e in sources for the

Page

74 74

grm..'ing p ig 75

1 1 . 2 . 3

( i ) Introduct ion

( i i) The diges t ibilit y of c rude prot ein and amino acids in a cas e in , amino acid b3sed

7 5

(basal) diet 7 5

( a ) Experimen tal procedure ( b ) Resu l t s

( c) Discuss ion

( i ii) The apparent ileal dige s t ib il i t y of amino acids in barley- , p ea- , meat-and-bone­

and f ish-meal

( a ) Exper imen tal procedure ( b ) Results

( c) Discuss ion

A comparison o f the apparent digestibility o f dietary crude prot ein i n t h e ra t and p i g as det ermined a t the t e�inal ileum and over the en tire digest ive t ract

( i ) ( ii) ( i ii) ( iv)

Introduct ion

Experimental procedure Resul t s

Discussior.

75 7 9 8 1

83 83 85 86

90 9 0 9 1 9 3 94

11.2.4

II . 2 . 5

PART I l l .

An assessment o f the accuracy of appa rent ileal amino acid d igest ibility as a measure of the d igestion and absorpt ion of amino acids by the growing pig

( i ) ( i i ) ( iii) ( iv)

Int roduct ion

Experimental procedure Resul ts

Discussion

Summary and Conclusions

THE PREDI CTION OF DI ETARY PROTEIN QUALITY BASED ON A MODEL OF THE DIGESTION AND HETABOLISM OF

NITROGEN IN THE GROWING PIG

Chapt er 1. Review of Lit erature I ll. 1 . 1 Introduct ion

Ill. 1 . 2

I I I . l . J Ill . 1 . 4

Ill . 1 . 5

Pro t ein quality : An appraisal o f methods of d e t e rminat ion

Simulat ion mod el l ing

Models in animal nut rit ion Conclusion

Chapter 2 . The Development o f a Hodel Simulat ing the Diges t ion and Hetabol ism of Dietary N i t rogen in the Growing

Page

9 7 9 7 9 8 1 0 ') 1 0 5 1 0 7

1 0 9

1 1 0 1 1 0

1 1 0 1 1 2 1 1 3 1 1 5

P i g ( 20 to 80 Kg Livewe ight ) 1 1 6

I I I . 2 . 1 II I . 2 . 2

II I . 2 . 3 I I I . 2 . 4

Introduction

Design of the model ( i )

( i i)

Int roduction

Descript ion of the model Evaluati on o f the mod el

Discussion

APPENDI CES BIBLIOGRAPHY

1 1 6 1 1 7 1 1 7 1 2 1 13 1 142 150 160

Tab l e

l. l. 1

I. 1. 2

I. 2. 1

I. 2. 2

I . 2. 3 I. 2. 4

I . 2. 5 I . 2. 6

I . 2. 7

I . 2 . 8

I . 2 . 9

LIST OF TABLES

Requ iremen ts of the growing pig for some

amino a c i ds ( Agricul tural Resea rch Counc il , 1 9 81) Amino a c i d composit ion of ideal pro t e in for the growing pig ( l ysine ⁼ 100)

The d e t e rmined amino acid composi t ion of enzym­

at ically hydrolysed casein and amounts of synthe t i c amino a c i ds added to provide the sole pro t e in

source o f the basal diet

Ingre d i en t composi t ion o f the basal d iet Nut ri en t composit ion of the basal diet

The amino a c id composi t ion of the basa l d i et Feed ing l evel of the basal diet

The ingred ient and nut r i ent composi t ions o f the cont ro l d iet

Mean apparent fae cal di gest ib i l i t y values d e t e r-

+ +

mined a t three d i et ary levels of the (Na + K - Cl-) factor

Mean met abolisab i l i t y values d e t e rmined at three , + +

d i e t a ry l evels of the (Na + K - Cl ) factor Mean val ues of daily urinary t o t al nit rogen exc re t ion ( g/ Kg 0 " 75 ) at three d i e tary levels

+ +

of the (Na + K - Cl ) factor

I . 2. 10 Mean values of daily urina ry urea excret ion ( g/Kg 0 " 7 5 ) at three d i e ta ry levels of the

+ + -

(Na + K - Cl ) factor

I . 2 . 1 1 Ingre d i en t composi t ions of the basal and experimental diets

1 . 2 . 12 Mean daily urinary urea excret ion (mg/Kg0 " 7 5 ) o f pigs f e d a t two d i e tary gross energy levels

ix

Page

5

1 1

2 5 2 6 2 7 2 8 2 9 3 4

3 7

3 7

3 8

38 4 1

42

Tab le Page I . 2 . 1 3 The mean urinary total nit rogen excret ion

(mg/Kg 0' 7 5 / d) o f p igs fed the basal diet

1 . 2 . 1 4 Est imates of the endogenous ur inary n i t rogen

loss of growing pigs

I . 2 . 15 Ingred ient compos i t ion o f the protein-f ree diet

1 . 2. 1 6 Livewe igh ts o f the boars during the urinary collect ion periods

I 2 ^{• •} 1 7 �� ^1· ean a1 y ur1nary excre t 1ons d ·1 · · ( mg/Kg 0' 7 5 ) of urea , urea nit rogen and total nit rogen for pigs fed the basal and rrot ein- free diets

I . 2 . 18 Comparison o f the es t ima te o f ideal amino acid balance found in the present s tudy wit h that recommende d by the Agricult ural Res earch Council ( 1 9 8 1 )

I . 2 . 1 9 Comparison o f t h e est imate of ideal amino acid balance found in the present s t udy with the amino acid pat t erns of pig musc l e , l iver and in test inal t i ss ues

I I . 2 . 1

I I . 2 . 2 I I . 2 . 3

I I . 2 . 4

11.2.5

I I . 2 . 6

I I . 2 . 7

Ingredient compos i tion o f a cas ein , amino acid b as ed ( basal) d i et

Ingredient composi tion o f a protein- free diet The diges t ib i l i ty of crude pro t ein in the casein , amino acid based (basal ) diet

The ileal d iges tibility of amino acids in the casein , amino acid based (basal ) diet

The ingredient compos i t ions ( g/Kg air- dry weight ) of the d iets

Mean coe f ficients o f apparent ileal amino acid digestibility in four dietary pro t e in sources fo r the grow ing pig

Predicted and determined appar ent i l eal amino acid digest ib i l i t ies in a mixed diet containing four protein sources

45

4 5 4 8 51

5 1

58

59

7 7 78

79

80

84

87

89

X

Tab le I I . 2 . 8

I I . 2 . 9

The ingredi ent composit ion ( g/Kg air-dry weigh t ) o f four diets for the growing ra t

The mean apparent diges t ib i l i t y o f crude pro t e in

(� S . E. ) in th ree di et ary ingred ients as measured

Page 92

on ileal digesta or faeces in the rat and the pig 9 5 11 . 2 . 1 0 1h e ingredient and nut rient compo s i t ions o f the

barley-based diet

11 . 2 . ^ll The amino acid balance of the barl ey-based diet compared w i th an est imate o f ideal amino acid balance

11 . 2 . 1 2 The ingredient and nut r ient compos i t ions of the enzymat ically hydrolysed casein , synthe t i c amino aci d control diet

11. 2 . 1 3 The feeding s cale for pigs fed the barley-based and cont ro l diets

11. 2 . 1 4 Mean ( � S . E . ) daily l iveweight gains and lean and to tal fat con t ents of the ham j oint

I I I . 2 . l

I I I . 2 . 2

I II . 2 . 3

I I I . 2 . 4

I II . 2 . 5

I II . 2 . 6

A s ug ges ted procedure for the cons truct ion o f a model ( Baldwin , 1 9 76 )

U rinary n i t rogen (N) excret ion ; act ual ( balance experimen t ) vs . predicted ( s imula t ion mod el ) Body pro tein depos i t ion (Pd) ; actual (balance experiment ) vs. predicted ( simulat ion model ) Ingred ient compo s i t ion of the d iet fed in the s t udy of Henderson et al. ( 1 9 80 )

The ingredi ent composit ions ( g/Kg air-dry weight ) o f some commercial pig grower diets

Model .p redict ion o f t he utili�at ion o f dietary c rude prote in at three levels of food intake

99

lOO

1 02

104

1 0 5

1 1 7 1 34

1 36

1 3 8 1 4 6 1 4 7

x i