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Hulless barley as an alternative energy source for
growing–finishing pigs on growth performance, carcass
quality, and nutrient digestibility
*
Jih-Fang Wu , Ching-Shen Cheng, I-Te Yu, Jung-Nan Hsyu
Department of Production Management, Pig Research Institute Taiwan, Miaoli, Taiwan Received 19 May 1998; received in revised form 7 April 1999; accepted 26 October 1999
Abstract
One feeding trial and one digestion trial were conducted to compare hulless barley and corn in terms of their effects on pig performance, carcass traits, and nutrient digestibility. In the feeding trial, 32 crossbred pigs (Duroc3Landrace3Yorkshire), averaging 22.3 kg each, were randomly assigned to two treatments as follows: (1) a corn–soybean meal control diet, and (2) all the corn of the control diet replaced by hulless barley. In the digestion trial, eight crossbred gilts (Duroc3Landrace3 Yorkshire), averaging 65.08 kg, were used to determine the digestibility of the diets. In the feeding trial, the average daily gain (ADG) of pigs fed the hulless barley diet was significantly higher than that of pigs fed the corn diet during the grower period, but the pigs fed the hulless barley diet were not significantly different in ADG from the pigs fed the corn diet during the finisher and overall periods. The daily feed intake of pigs fed the hulless barley diet was not significantly different from that of pigs fed the corn diet during the grower, finisher, and overall periods. The feed-to-gain ratio of pigs fed the hulless barley diet was not significantly different from that of pigs fed the corn diet during the grower period, but the pigs fed the hulless barley diet required less feed per unit of gain than those fed the corn diet during the finisher and overall periods. The dressing percentage, carcass length, mean backfat thickness, and loin eye area of pigs fed the hulless barley diet were not significantly different from those of pigs fed the corn diet. In the digestion trial, the apparent digestion coefficients of dry matter and energy of pigs fed the hulless barley diet were not significantly different from those of pigs fed the corn diet. The coefficient for nitrogen tended to be lower for hulless barley than for corn (P,0.07). From these results, hulless barley is concluded to be a potential alternative energy source for use in swine diets. 2000 Elsevier Science B.V. All rights reserved.
Keywords: Hulless barley; Growth; Carcass trait; Digestibility; Swine
source of swine diets is cereal grains. In some parts 1. Introduction
of the world, corn is the major cereal while it is wheat, barley, or sorghum in other places. Due to In many parts of the world the major energy
their low protein content these cereals have to be *Corresponding author. Present address: Pig Research Institute
associated with protein sources such as is generally Taiwan, P.O. Box 23, Chunan, Taiwan. Tel.: 1886-37-672-352;
done with soybean meal. The usefulness of hulless fax: 1886-37-684-723.
E-mail address: [email protected] (J.-F. Wu) barley has been studied since the 1970s (Mitchall et 0301-6226 / 00 / $ – see front matter 2000 Elsevier Science B.V. All rights reserved.
Table 1 al., 1976), but the poor yield and the fragility of the
Chemical analysis of corn, hulless barley, and soybean meal (as grain did not allow its development.
fed basis) The performance of pigs fed barley-based diets is
Component Corn Hulless Soybean
generally inferior to that of pigs fed diets based on
barley meal wheat or corn (Hollis and Palmer, 1971). The major
Dry matter (%) 86.89 86.45 88.21 factors responsible for the lower nutritional value of
Crude protein (%) 7.77 13.26 40.19 barley are its relatively high crude fiber content and
Ash (%) 1.21 1.48 6.05
resulting low energy level (Larson and Oldfield, Calcium (%) 0.17 0.11 0.45 1961). Since a large proportion of the crude fiber Phosphorus (%) 0.23 0.32 0.64 content of barley is contained in the hull fraction Crude fat (%) 3.60 1.55 2.21
Crude fiber (%) 2.30 2.37 5.58
(Bell et al., 1983), it is possible that the removal of
Gross energy (MJ / kg) 16.16 16.10 17.02 the hull from barley could substantially improve its
nutritive value. In hulless barley, unlike covered barley, the hull is weakly attached to the seed kernel
and is easily removed during harvesting. The energy signed to two treatment groups with four replications content of hulless barley is much higher than that of based on sex and weight. In each replication, the pigs covered barley (Mitchall et al., 1976; Perez et al., were housed in two concrete-floored pens of four 1980). Several researchers have indicated that the (one pen per treatment) measuring 3.232.6 m. They performance of pigs fed hulless barley is superior to had feed and water ad libitum. Pigs were weighed at that of pigs fed hulled barley (Gill et al., 1966; weekly intervals. When the mean weight of the pigs Newman et al., 1968, 1980; Bhatty et al., 1979); in the pen was higher than 60 kg, the diet was other authors have observed little or no improvement changed from the grower to finisher phase. Indi-in performance (Mitchall et al., 1976; Aherne and vidual pigs were slaughtered at 95–100 kg, about Spicer, 1986; Thacker et al., 1988; Bell and Keith, 5.5–6.0 months of age, at which time carcass traits 1993, 1994). The objective of this study was to of pigs were measured (Boggs and Merkel, 1979). compare the nutritive value of hulless barley- and Feed consumption was determined on a pen basis at corn-based diets as estimated from pig performance, the time of the weekly weighing. The two treatments carcass traits, and nutrient digestibility. were: (1) a corn-based diet as control, and (2) a hulless barley-based diet. For each treatment, a grower and a finisher diet was formulated. In each 2. Materials and methods diet the level of soybean meal was determined in order to provide 0.70 and 0.60% digestible lysine 2.1. Feedstuffs during the growing (20–60 kg) and the finishing (60–100 kg) periods, respectively (Table 2). All Corn and hulless barley were processed by a other nutrients were present in sufficient amounts to 20-HP full circle hammermill equipped with differ- meet pig requirements (NRC, 1988).
ent size screens. The 6.4- and 3.2-mm hammermill
grind screens were used for corn and hulless barley 2.3. Digestion trial diets, respectively. Soybean meal was used to
Table 2
Composition of diets
Ingredient Corn-based Hulless
barley-control diet based diet
Grower Finisher Grower Finisher
Corn, ground 73.10 77.15 – –
Hulless barley, ground – – 83.27 88.00
Soybean meal, solv., 44% 24.36 20.48 12.31 7.74
Soybean oil – – 1.50 1.50
Dicalcium phosphate 1.77 1.61 1.52 1.48
Limestone, pulverized 0.14 0.06 0.58 0.38
L-Lysine (78.4%) 0.03 – 0.22 0.20
Salt 0.40 0.50 0.40 0.50
a
Vitamin premix 0.10 0.10 0.10 0.10
b
Trace mineral premix 0.10 0.10 0.10 0.10
Calculated nutrient composition
Digestible lysine (%) 0.70 0.60 0.71 0.60
DE (MJ / kg) 14.36 14.38 14.34 13.98
Analysed nutrient composition
Crude protein (Nx6.25, %) 15.62 14.32 15.93 14.50
Calcium (%) 0.82 0.72 0.78 0.76
Phosphorus (%) 0.68 0.66 0.65 0.61
Crude ash (%) 4.55 4.50 4.30 4.25
Crude fat (%) 2.72 2.90 3.17 3.57
Crude fiber (%) 3.54 2.92 2.62 2.74
a
Each kg of vitamin premix contained: vitamin A, 4 000 000 IU; vitamin D , 600 000 IU; vitamin E, 20 g; vitamin B , 4 g; vitamin B ,3 2 12 0.02 g; pantothenic acid, 12 g; niacin, 40 g; folic acid, 0.4 g; biotin, 0.01 g; choline chloride, 50 g.
b
Each kg of trace mineral premix contained: Zn, 100 g; Fe, 140 g; Cu, 20 g; Mn, 4 g; I, 0.2 g; Se, 0.1 g.
feed intake and environment; Foley catheters were feed efficiency or pig for weight gain was considered put into the bladder of gilts, and the final 5 days as the experimental unit, and the data were analyzed were devoted to total fecal collection. Pigs were fed as a randomized complete block using the GLM the experimental diets at 3.0% of body weight daily procedure of SAS (1984). Means were separated on in two equal feedings. Water was given with meals at the basis of analysis of variance procedures using a a ratio of 2.0–2.5:1.0. Ferric oxide at 1.0% in the t-test. In the digestion trial, the pig was considered as
diet was used as a marker for collection of feces. It the experimental unit, and the data were analyzed was mixed into the diets to be fed at the beginning statistically by using analysis of variance as previ-and end of collection period. A sample was taken ously described.
and retained for dry matter, nitrogen, and energy determination.
4. Results
3. Analytical methods 4.1. Growth trial
Table 3
Growth performance of pigs fed diets based on corn or hulless barley
a
Item Corn-based Hulless barley- S.E.M.
control diet based diet
No. of pigs 16 16
Average body weight(kg)
Initial 22.40 22.17 0.46
At end of grower period 63.46 60.77 0.78
Final 98.20 98.12 0.72
Average daily gain(kg)
b c
Grower period 0.671 0.714 0.01
Finisher period 0.882 0.898 0.04
Overall period 0.748 0.792 0.01
Daily feed intake(kg)
Grower period 1.72 1.76 0.03
Finisher period 2.84 2.67 0.11
Overall period 2.15 2.15 0.04
Feed /gain
Grower period 2.56 2.46 0.03
b c
Finisher period 3.24 2.97 0.03
b c
Overall period 2.87 2.72 0.02
a
Standard error of the mean. b,c
Means in the same row bearing different superscript letters are significantly different (P,0.01).
diet was not significantly different from that of pigs The carcass characteristics of pigs fed diets based fed the corn diet during the finisher and overall on corn or hulless barley are shown in Table 4. The periods. The daily feed intake of pigs fed the hulless dressing percentage, carcass length, mean backfat barley diet was not significantly different from that thickness, and loin eye area of pigs fed the hulless of pigs fed the corn diet during the grower, finisher, barley diet were not significantly different (P.0.05) and overall periods. The feed-to-gain ratio of pigs from those of pigs fed the corn diet.
fed the hulless barley diet was not significantly
different (P.0.05) from that of pigs fed the corn 4.2. Digestion trial diet during the grower period, but the pigs fed the
hulless barley diet required less (P,0.01) feed per The apparent digestibility coefficients of pigs fed unit of gain than those fed the corn diet during the diets based on corn or hulless barley are shown in finisher and overall periods. Table 5. The coefficients of dry matter and energy of
Table 4
Carcass characteristics of pigs fed diets based on corn or hulless barley
a
Item Corn-based Hulless barley- S.E.
control diet based diet
Dressing percentage (%) 80.30 79.76 1.67
Carcass length (cm) 81.93 81.68 2.06
Mean backfat thickness (cm) 2.77 2.95 0.31
2
Loin eye area (cm ) 39.33 39.88 5.55
a
Table 5 on corn or hulless barley were similar. Bell and Apparent digestibilities of finisher diets based on corn or hulless Keith (1993) reported that three types of wheat,
a barley
hulless barley, and corn replacing 0, 25, 50, 75 and b
Item Corn-based Hulless barley- S.E. 100% of the regular barley in the grain mixture had control diet based diet
similar effects on backfat, lean yield, and carcass Dry matter (%) 87.67 87.64 0.65 index, but pigs fed wheat diets had higher dressing Energy (%) 88.53 88.40 0.63 percentages than those fed a hulless barley or corn
c d
Nitrogen (%) 87.39 83.42 1.99
diet. This result may have been affected by differ-a
Dry matter basis. ences in the nature and level of fiber and by the
b
Standard error.
amount of protein supplementation required. Gros-c,d
Means in the same row bearing different superscript letters
jean and Gatel (1987) found that the carcass yield are different (P,0.07).
was lower with barley than with corn or wheat diets. Variations of carcass yield can be explained by fiber or fat contents, which are responsible for the energy pigs fed the hulless barley diet were not significantly content of diets. Beames and Natoli (1969), Bouard different (P.0.05) from those of pigs fed the corn and Leuillet (1975), and Patience et al. (1977) diet. The pigs fed the hulless barley diet had a lower showed that crude fiber leads to lower carcass yield (P,0.07) apparent digestion coefficient of nitrogen with incorporation of milling by-products. On the than those fed the corn diet. contrary, Davies and Lucas (1972), Seerley et al. (1978), and Castaing et al. (1982) showed that incorporation of fat in the diet leads to better carcass
5. Discussion yield.
The results of the digestion trial showed that the Diets were formulated by using values of 14.77, digestibilities of dry matter and energy of pigs fed 14.43, and 14.60 MJ / kg for digestible energy (DE) the hulless barley diet were similar to those of pigs content of corn, hulless barley, and soybean meal, fed the corn diet. The pigs fed the hulless barley diet respectively. Since the energy content of the hulless had a lower digestibility of nitrogen than those fed barley diet was slightly lower than that of the corn the corn diet. The reason for this was the lower level diet, 1.5% soybean oil was added to the hulless of soybean meal used in the hulless barley diet. barley diet to equalise the DE contents of the two Estimated digestibility of energy in corn was 83%, in diets (Table 2). Protein and lysine contents of 7.7 hulless barley 81% (Bell and Keith, 1991), and in and 0.22%, 13.3 and 0.43%, and 40.2 and 2.59% Hy-320 wheat 82% (Bell and Keith, 1989). The were used for corn, hulless barley, and soybean apparent digestibility of crude protein was 78% in meal, respectively. The diets were balanced for corn, 67% in hulless barley, and 79% in Hy-320 digestible lysine by adding 0.22 and 0.20% synthetic wheat. Bell and Keith (1993) pointed out that the lysine to the hulless barley diets fed during the superiority of corn diets may be due to the higher grower and finisher phases, respectively (Table 2). energy digestibility of corn. But the relatively large The results of the growth trial indicated that the amount of protein supplement required in corn diets overall average daily gain and daily feed intake of reduced the differences among diets in digestible pigs fed the diet containing hulless barley were energy contents and resulted in neutral detergent similar to those of pigs fed the diet containing corn. fiber levels of 14.8 and 14.0% for hulless barley and The overall feed efficiency of pigs fed the hulless corn diets, respectively. This also indicated a pos-barley diet was better than that of those fed the corn sible advantage for corn diets (Just, 1982; Bell et al., diet. However, Gill et al. (1966) reported that feed 1983).
Bhatty, R.S., Christison, G.I., Rossnagel, B.G., 1979. Energy and consumption is required to maintain equivalent gain.
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