Feedipedia
Animal feed resources information system
Feedipedia
Feedipedia

Sunflower hulls and sunflower screenings

Datasheet

Description
Click on the "Nutritional aspects" tab for recommendations for ruminants, pigs, poultry, rabbits, horses, fish and crustaceans
Common names 
  • Sunflower hulls, sunflower shells
  • Sunflower screenings
Description 

Sunflower hulls are the by-product of the dehulling of sunflower seeds before they are used for oil extraction or as bakery ingredients (AAFC, 2007). Sunflower seeds contain about 20-30% hulls that are often removed before oil extraction due to their deleterious effects on oil presses and because they reduce the quality of both oil and meal (Kartika, 2005). Decreasing the hull content by 1% improves pressing capacity by 2.5%. A well-managed dehulling process yields seeds with 8-12% hulls remaining on the kernels (Campbell, 1983). 100 kg of seeds having 25% hulls yielded 16.5 kg of hulls in an experiment where 66% of the hulls were removed (Carré, 2009).

Dehulling is done after cleaning the seeds and drying them down to 5% moisture, which facilitates kernel-hull separation (Kartika, 2005). The usual process consists in cracking the seeds by the mechanical action of centrifugal or pneumatic shellers. The resulting blend is winnowed to separate the hulls from the kernels. In new sunflower varieties, breeders have enhanced oil content at the expense of hulls, resulting in seeds with thinner hulls that are difficult to remove: these varieties remain undecorticated and do not yield sunflower hulls (Carré, 2009; Grompone, 2005; Campbell, 1983).

Sunflower hulls are light in weight and bulky, and are, therefore, costly and impractical to transport. They are burned as fuel to power oil mills but only half of the hulls available can be used on-site for energy production. The remaining half has to be transported off-site, to provide energy or for other purposes, such as composting, bedding material, or as a low-quality roughage for livestock (Dorrell et al., 1997; Carré, 2009).

Sunflower screenings are a mixture of variable amounts of residues including hulls, groats, lightweight or broken seeds, heads, sclerotia bodies, weed seeds, chaff, joints, straw, elevator dust and floor sweepings (Lardy et al., 2009).

Distribution 

Sunflower hulls are costly to transport because of their low density and are then only available close to sunflower oil mills (Dorrell et al., 1997). Some mills grind the hulls into a flour, resulting in a denser product (250 kg/m3 vs. 70-100 kg/m3) that is easier and less expensive to transport (Borredon et al., 2011).

Nutritional aspects
Nutritional attributes 

Sunflower hulls are a highly fibrous ingredient, rich in insoluble non-starch polysaccharides. They often contain more than 50% crude fibre or ADF, 70-85% NDF and 15-25% lignin. The protein and oil content are low but not negligible (about 7% and 5% respectively) due to variations in the amount of kernel fragments. Sunflower hulls have a low nutritive value for all animal species and are mostly used for animals that have specific fibre requirements, such as ruminants and rabbits (Cancalon, 1971).

The nutritive value of screenings will depend on the included amount of fibrous materials such as stalks and hulls, as in large amounts these will reduce the nutritive value. According to the proportion of whole seeds and groats, protein and fibre content may be equivalent to good quality hays or higher (Lardy et al., 2009). Their composition is close to that of hulls, with more protein and oil and less fibre when seeds fragments are present in larger amounts.

Ruminants 

Sunflower hulls are a very poor quality roughage with a high fibre content and a low digestibility (DM digestibility 18%; Alibes et al., 1990). Consequently, limited amounts of sunflower hulls should be included in diets (Dinusson et al., 1973) and should constitute less than 50% of the total roughage (Sharma et al., 1988). They are well consumed when finely ground and included in pelleted feeds (Dinusson et al., 1973).

Alkali treatments (NaOH, KOH or NH4OH) do not improve the nutritive value of sunflower hulls unless high doses are used (Sharma et al., 1988).

Growing cattle

Sunflower hulls may be included at up to 20% to increase the total fibre content in the diets of dairy heifers or to provide roughage in high-grain rations for growing or finishing beef cattle (Lardy et al., 2009).

Dairy heifers

Sunflower hulls included at 10 to 40% of the diet decreased nutrient digestibility (DM, CP, ADF). At 27%, the average daily gain was 1360 g/d and the feed efficiency was higher than for the control diet (+ 21%). A higher level of sunflower hulls in the diet (50%) was detrimental to DM intake and growth (Park et al., 1982).

Growing steers

Unground sunflower hulls introduced at 5 or 10% as roughage in the diet of fattening steers (374 kg) resulted in lower daily gains and DM intake (1240 vs. 1500 g/d and 0.766 kg/d vs. 0.840 kg/d respectively). However, using sunflower hulls could be cost-effective at this inclusion rate (Pritchard et al., 1990).

Sheep

In growing lambs, untreated or alkali-treated (NaOH, KOH or NH4OH) sunflower hulls included at 25% of the diet (replacing the same amount of alfalfa hay) had no effect on DM intake (1.1 to 1.5 kg/d), DM digestibility (63-66%) and daily weight loss (-0.11 kg/d) (Sharma et al., 1988).

Pigs 

Growing pigs

Sunflower hulls are not a suitable feed ingredient for growing pigs due to the large amount of insoluble fibre that they contain. However, sunflower hulls have been tested as a means to prevent or alleviate oesophago-gastric lesions in growing pigs. It was shown that a small amount of hulls (5%) added to a finely ground diet had a positive effect on animal health, but they were detrimental to pellet quality (Dirkzwager et al., 1998).

Sows

Feeding additional fibre to gestating sows has a generally positive effect on the number of pigs born alive and weaned. Sunflower hulls fed at 22% of the diet to gestating sows resulted in + 0.5 live piglets born and + 0.2 piglets weaned per litter (Reese et al., 2008). A high-fibre diet containing 35% ground sunflower hulls fed to pre-pubertal gilts slowed growth and pre-lactation mammary development but later enhanced sow lactation performance (Lyvers-Peffer et al., 2001).

Poultry 

Little information is known about the nutritive value of sunflower hulls in poultry. Up to 4-5% sunflower hulls can be introduced in broiler diets without negatively affecting performance, or the size of the digestive tract (Arija et al., 1998; Viveros et al., 2009). However, sunflower hulls are not a good ingredient for poultry: dehulled sunflower meals have a better ME than non-dehulled meals and there is a very strong negative correlation between the ME value of the meals and their fibre content (Villamide et al., 1998).

Rabbits 

In rabbit feeding, sunflower hulls can be considered as a safe ingredient. They are mainly a source of fibre, valuable for their very high lignin content. In compound feed diets, adding sunflower hulls makes it possible to reach the minimum level of lignin recommended for maintaining the digestive health of rabbits (minimum 5.0-5.5% according to the type of rabbits; Gidenne et al., 2010). The incorporation of sunflower hulls in the diets of growing rabbits reduces mortality caused by diarrhoea (Gippert et al., 1984). However, their contribution to energy supply is reduced because of their low energy digestibility (20 to 25%), normally associated with the high lignin level. The DE of sunflower hulls is about 4.4-5.5 MJ/kg DM. Similarly, the protein supplied by sunflower hulls is low as a poor protein content is combined with questionable protein digestibility values (measured values vary from 20% to more than 100%; Fernandez Carmona et al., 1996; Gippert et al., 1988; Garcia et al., 1996a).

In balanced diets, the inclusion rate of sunflower hulls can be increased up to 15-20% without reducing growth and feed efficiency in growing rabbits (Martina, 1983; Gippert et al., 1988; Nicodemus et al., 2002), and reproductive performance in breeding does (Nicodemus et al., 2007). For experimental purposes, sunflower hulls were incorporated at up to 24 and 32% of the diet (Garcia et al., 1996a; Beltran et al., 1984; Chamorro et al., 2007), and in one trial up to 62 % (Garcia et al., 1996b) without causing health problems.

Nutritional tables
Tables of chemical composition and nutritional value 

Avg: average or predicted value; SD: standard deviation; Min: minimum value; Max: maximum value; Nb: number of values (samples) used

Main analysis Unit Avg SD Min Max Nb
Dry matter % as fed 90.7 1.0 88.7 93.1 24
Crude protein % DM 7.0 1.8 4.7 11.1 28
Crude fibre % DM 50.8 6.9 33.3 59.3 32
NDF % DM 74.7 10.9 46.5 85.1 17
ADF % DM 60.1 3.5 53.4 66.5 17
Lignin % DM 22.2 3.9 12.9 30.9 18
Ether extract % DM 5.2 2.1 2.5 9.8 21
Ash % DM 3.8 0.6 3.1 5.7 25
Starch (polarimetry) % DM 3.4 2.6 4.3 2
Total sugars % DM 1.5 2.0 0.3 4.5 4
Gross energy MJ/kg DM 20.2 0.7 19.5 21.9 8 *
 
Minerals Unit Avg SD Min Max Nb
Calcium g/kg DM 4.4 1.7 2.3 7.3 10
Phosphorus g/kg DM 1.3 0.7 0.5 2.6 8
Potassium g/kg DM 11.9 7.7 16.1 2
Sodium g/kg DM 0.1 0.0 0.0 0.1 3
Magnesium g/kg DM 2.6 1.4 3.8 2
Manganese mg/kg DM 16 5 26 2
Zinc mg/kg DM 23 13 33 2
Copper mg/kg DM 10 5 14 2
Iron mg/kg DM 137 134 140 2
 
Amino acids Unit Avg SD Min Max Nb
Arginine % protein 4.9 4.9 5.0 2
Cystine % protein 2.2 1.6 2.8 2
Glycine % protein 8.7 1
Histidine % protein 3.0 2.7 3.2 2
Isoleucine % protein 3.6 3.4 3.9 2
Leucine % protein 4.6 4.3 5.0 2
Lysine % protein 5.1 0.7 4.3 5.7 3
Methionine % protein 2.6 0.8 1.6 3.1 3
Phenylalanine % protein 3.7 3.6 3.9 2
Serine % protein 7.9 1
Threonine % protein 5.4 3.9 7.0 2
Tryptophan % protein 1.1 1
Valine % protein 4.0 3.4 4.5 2
 
Ruminant nutritive values Unit Avg SD Min Max Nb
DM digestibility, ruminants % 18.2 1
Nitrogen degradability (effective, k=6%) % 40 1
 
Pig nutritive values Unit Avg SD Min Max Nb
Energy digestibility, growing pig % 10.3 *
DE growing pig MJ/kg DM 2.1 *
MEn growing pig MJ/kg DM 1.5 *
NE growing pig MJ/kg DM 0.0 *
Nitrogen digestibility, growing pig % 35.5 1
 
Rabbit nutritive values Unit Avg SD Min Max Nb
Energy digestibility, rabbit % 24.4 *
DE rabbit MJ/kg DM 4.9 0.6 4.4 5.5 3
Nitrogen digestibility, rabbit % 33.5 19.2 47.7 2
MEn rabbit MJ/kg DM 4.8 *

The asterisk * indicates that the average value was obtained by an equation.

References

AFZ, 2011; Alibes et al., 1990; Arija et al., 1998; Ashes et al., 1978; Bourdon, 1985; Chandra et al., 1985; Chapoutot et al., 1990; Enueme et al., 1987; Fernandez Carmona et al., 1996; Garcia et al., 1996; Gippert et al., 1988; Jordan et al., 1970; Karunajeewa et al., 1989; Leroy et al., 1949; Michalet-Doreau et al., 1980; Noblet, 2001; Pereira et al., 1999; Perez et al., 1984; Perez et al., 1986; Peteva-Vantcheva et al., 1976

Last updated on 24/10/2012 00:45:11

Main analysis Unit Avg SD Min Max Nb
Dry matter % as fed 90.1 1.3 86.8 93.1 39
Crude protein % DM 9.1 3.0 4.8 15.3 48
Crude fibre % DM 42.2 13.7 19.4 59.0 46
NDF % DM 71.7 12.9 42.1 84.7 18
ADF % DM 57.2 8.3 35.0 66.5 20
Lignin % DM 20.9 3.9 12.8 28.9 19
Ether extract % DM 8.5 4.1 2.5 17.8 39
Ash % DM 7.1 4.1 3.2 14.3 42
Starch (polarimetry) % DM 2.7 1.5 1.2 4.3 3
Total sugars % DM 1.5 2.0 0.3 4.5 4
Gross energy MJ/kg DM 20.1 1.4 18.3 23.6 13 *
 
Minerals Unit Avg SD Min Max Nb
Calcium g/kg DM 7.9 5.9 2.3 19.5 16
Phosphorus g/kg DM 2.5 1.8 0.5 6.5 14
Potassium g/kg DM 11.6 4.2 7.7 16.1 3
Sodium g/kg DM 0.1 0.0 0.0 0.1 4
Magnesium g/kg DM 2.6 1.4 3.8 2
Manganese mg/kg DM 16 5 26 2
Zinc mg/kg DM 23 13 33 2
Copper mg/kg DM 10 5 14 2
Iron mg/kg DM 137 134 140 2
 
Amino acids Unit Avg SD Min Max Nb
Arginine % protein 4.9 4.9 5.0 2
Cystine % protein 2.2 1.6 2.8 2
Glycine % protein 8.7 1
Histidine % protein 3.0 2.7 3.2 2
Isoleucine % protein 3.6 3.4 3.9 2
Leucine % protein 4.6 4.3 5.0 2
Lysine % protein 5.1 0.7 4.3 5.7 3
Methionine % protein 2.6 0.8 1.6 3.1 3
Phenylalanine % protein 3.7 3.6 3.9 2
Serine % protein 7.9 1
Threonine % protein 5.4 3.9 7.0 2
Tryptophan % protein 1.1 1
Valine % protein 4.0 3.4 4.5 2
 
Ruminant nutritive values Unit Avg SD Min Max Nb
OM digestibility, Ruminant % 52.4 1
Energy digestibility, ruminants % 50.5 *
DE ruminants MJ/kg DM 10.1 *
ME ruminants MJ/kg DM 8.1 *
Nitrogen digestibility, ruminants % 43.4 1
Nitrogen degradability (effective, k=6%) % 40 1
 
Pig nutritive values Unit Avg SD Min Max Nb
Energy digestibility, growing pig % 23.8 *
DE growing pig MJ/kg DM 4.8 *
MEn growing pig MJ/kg DM 4.2 *
NE growing pig MJ/kg DM 1.9 *
Nitrogen digestibility, growing pig % 35.5 1
 
Rabbit nutritive values Unit Avg SD Min Max Nb
Energy digestibility, rabbit % 24.5 *
DE rabbit MJ/kg DM 4.9 0.6 4.4 5.5 3
MEn rabbit MJ/kg DM 4.8 *
Nitrogen digestibility, rabbit % 33.5 19.2 47.7 2

The asterisk * indicates that the average value was obtained by an equation.

References

AFZ, 2011; Alibes et al., 1990; Arija et al., 1998; Ashes et al., 1978; Bourdon, 1985; Chandra et al., 1985; Chapoutot et al., 1990; Enueme et al., 1987; Fernandez Carmona et al., 1996; Garcia et al., 1996; Gippert et al., 1988; Jordan et al., 1970; Karunajeewa et al., 1989; Leroy et al., 1949; Michalet-Doreau et al., 1980; Noblet, 2001; Pereira et al., 1999; Perez et al., 1984; Perez et al., 1986; Peteva-Vantcheva et al., 1976

Last updated on 24/10/2012 00:45:45

References
References 
Datasheet citation 

Heuzé V., Tran G., Hassoun P., Lessire M., Lebas F., 2015. Sunflower hulls and sunflower screenings. Feedipedia, a programme by INRA, CIRAD, AFZ and FAO. http://www.feedipedia.org/node/733 Last updated on October 9, 2015, 14:22

English correction by Tim Smith (Animal Science consultant) and Hélène Thiollet (AFZ)
Image credits