of pigs

NOVA course 2009

Feed Technology and nutrition of pigs

Lectures 16.06.2009

Nils Petter Kjos

Processing of feeds

• Grinding and structure of feed

– Contents of fiber

– Physical status of the feed

• Feed intake

• Utilization of the feed

• Stomach alterations and stomach ulcer

• Pelleted feed/meal diet

• Heat treatment

Pelleted feed/meal diet

• Improves the technological characteristics of the feed (transport, feeding,

environments/less dust)

• Pelleted feed gives a better feed intake, both for piglets and grow-finish pigs

• Pellet quality is also of importance

Pelletsmatrise

Pellets matrix

Effect of pelleting on production performance in grow-finish pigs

(Skoch et al., 1983) Meal

feed

Cold pelleted

Pelleted at 85°C

Gain, kg/day 0.75 0.78 0.79

Protein digestibility, % 83.3 85.0 83.4

Pellet durability - 80.4 96.0

Functional properties in protein - pelleting

• Chemical changes under heat processing results in making of a pellet

– Gel formation

– Formation of fibrils and matrix

Chemical changes of proteins under processing

• Unfolding of protein structures without breaking or formation of covalent bindings

• Covalent cross binding

• Maillard reaction

• Formation of lysinoalanine, lanthionine or ornithinoalanine

• Formation of D-amino acids from L-amino acids

Gel formation

Intact protein Unfolded protein Gel

(Hoseney, 1994)

Heat treatment

• Most pelleting methods also gives a heat treatment of the feed

• Other methods; extruder and expander methods

• Gives an increased nutritive value, caused by:

– Gelatinization of starch

– Degradation of cells, and changed cell structure – Changed dissolution of the fibres

• Inactivation of antinutrients

• Reduced phytase-activity

• Pelleting and heat treatment in general improves

feed:gain in grow-finish pigs by 0.24 Feed Units

per kg weght gain

Source Feed:gain, difference compared to meal feed, Feed Unit/kg

Rapport nr. 385 -0.17

Rapport nr. 426 -0.17

Rapport nr. 475 -0.17

Rapport nr. 489 -0.26

Rapport nr. 534 -0.42

Average -0.24

Source: Landsutvalget for Svin, Danske Slakterier

Effect of pelleting on feed:gain in grow-finish pigs

Carbohydrate constituents in plant tissues

CWM

Starch

Possible effects of heat processing

Solubilisation of CW PS

Gelatinisation of starch

+/- influence on viscosity

+/- influence on WBC

Effect of heat treatment on physicochemical properties

Viscosity, mPa•s

WBC, g/g DM

Wheat Barley Wheat Barley Untreated (raw) 1.14 1.91 1.23 1.52

Cold pelleted 1.19 2.22 1.15 1.29

Pelleted, 60 °C 1.14 2.84 1.38 1.89 Pelleted, 75 °C 1.35 3.85 1.57 2.04 Pelleted, 90 °C 1.44 25.2 2.17 1.77

Expanded, 100 °C

1.82 902 1.73 1.28

Extruded 2.26 477 3.71 3.09

Possible impact of heat processing on feed structure and nutritional properties

• Better accessibility to nutrients for digestive enzymes

• Improved digestibility of nutrients in the

small intestine

• Better performance

• Reduced incidence of diarrhoea (?)

• More even weight of

piglets at 30 kg

Factors influencing rate and extent of starch degradation in the small intestine

• Gelatinisation

• Crystalline form

• Retrogradation

• Amylose/amylopectin ratio

• Particle size, texture

• Disruption of cell wall integrity

• Presence of non-starch polysaccharides (especially viscous forms)

• Presence of antinutrients (alpha-amylase

inhibitors, phytates, lectins, tannins, etc.)

Bygholm – sieve. Determination of

particle size distribution on farm level

Stomach alterations

Piglets - structure of stomach contents

• Coarsely grinded meal feed • Finely grinded pelleted feed

Increased feed structure

Effect of feed processing on performance and gut health

Feed

Grinding on hammer mill:

Fine

Pellets (2 mm)

Rough Pellets (4 mm)

Meal (4 mm) Daily weight gain,g (grow-finish pigs, 30 – 100 kg) 812 793 791

Feed:Gain (FEs/kg gain) 2.54 2.68 2.83

Lean percentage 59.5 59.6 59.7

Relative profitability (% in ralation to Fine Pelles) 100^a 83^b 67^c

Dry matter in stomach content, % 10.3^a 17.2^bc 21.3^c

Lactic acid bacterias, log CFU/g 7.6^a 7.4^ab 8.3^c

Lactic acid concentration in stomach, mmol/kg digesta 15.0 16.0 34.0

Stomach ulceration score 2.9^a 1.7^b 0.08^c

Salmonella positive pigs, %, serum analysis 12.9 5.6 2.8

Coliforms in stomach, log CFU/g 5.2^a 4.4^bc 4.2^c

Starch content in faeces, % of dry matter 0.2 1.7 5.7

Source: Jørgensen et al., 1999 a,b,c - Significant differences among treatments

Feed type

Production result Stomach/gut health

Fine pellet + + - -

Meal feed - - + +

Coarse pellet - +

Effect of feed structure on stomach/gut health

A healthy gut may reduce growth rate

• From January 1, 2006, antibiotic growth promoters are banned in EU. Alternative methods to promote growth and to prevent problems, f.ex. Diarrhoea in young pigs, has to be found.

• It is not enough just to use other feed additives and different feed processing methods as an alternative to promote growth and health, particularely if the goal is to aim for a high growth rate. Good management practices and high-quality feedstuffs is also important.

• If good health is achieved by altering the feed processing methods, growth rate may be reduced.

Bacteria kill bacteria

• Lactic acid bacterias (LAB) in the stomach/gut region may be stimulated. They can kill or inhibit harmful bacterias.

• LAB is produced by fermentation of the feed. This process takes time. The extra time may be gained by retaining the foor in the stomach for a longer time. The cost is that as long as the feed remains in the stomach, assimilation of nutrients can not take place.

• The fermentation process also costs energy

• Fermentation of wet mash before feeding, and coarse- milling of feed components, may promote gut health and growth.