Vol. 5(1996): 167-175 Feeding whole grain with pelleted diets to growing broiler chickens Tuomo Kiiskinen Agricultural Research Centre ofFinland, Institute ofAnimal Production, FIN-31600 Jokioinen, Finland In three trials with growing broilers (aged 12-8 days) the proportion of whole grain (WG) was in- creased step by step up to 30% (Trial 1) along with commercial starter (S) and grower (G) pellets or up to 40% (Trial 2) and 50% (Trial 3) with special balancer (BA) pellets (crude protein 250 g/kg). WG accounted for about 20%, 31% and 38% of the broilers’ total feed intakes, respectively. In Trial 1, the grain was exclusively wheat (W). In the other trials, also mixtures of wheat and barley (W:B 70:30, 50:50) were used. Crude protein analyses of feed remains revealed that birds did not to any considerable extent select between pellets and grain. Mixing wheat with S or G pellets reduced feed intake significantly (P<0.05) and, as a consequence, the growth rate decreased by 3-5%. However, the feed efficiency (FCR) of the SW birds was significantly (P<0.05) better than that of the control and GW birds. In Trial 2, the BAWG treatments reduced feed intake (P<0.05) and weight gain, but there were no significant differences in FCR. In Trial 3, the growth rate was similar with all the regimens, and birds fed the BAW diet consumed feed less (P<0.001) but more efficiently (P<0.001) than those fed the other diets. In each trial, the WG feedings increased markedly (50-90%) the empty gizzard weight. Fatness of broilers decreased significantly (P<0.05) when whole wheat was fed with the S diet (Trial 1) but not so when fed with the BA diet (Trials 2 and 3). The present results suggest that during the growing phase, broiler chickens can be fed efficiently with mixtures of a pelleted starter or a pelleted balancer diet and whole wheat which can partly be replaced by barley. Key words: poultry, balancer diet, growth, feed conversion, fatness, gizzard weight ntroduction Industrial complete diets for broiler chickens contain cereals up to 70%. Processing, handling and transport increase markedly the original price of whole grain. Therefore, it seems reas- onable to develop feeding regimens which base on the use of whole grain produced on the farm, mixing it with industrial starter or grower pel- lets. This regimen has become very common, especially in the northern countries. Feeding of whole wheat is started at 7-10 days of age, and the proportion ofwheat reaches a level of 25-30% at the end of the growing period. With this regi- men the supply of most nutrients and additives © Agricultural and Food Science in Finland Manuscript received March 1996 167 AGRICULTURAL AND FOOD SCIENCE IN FINLAND https://www.c-info.fi/en/info/?token=nd8sWQVoI-NdX4c_.SheAoR6j85XhjS_dOHqFSw.rwlYjyte4fo_vdMMXEdZg-IUpVmbwBDp6GC6O4JFgzDe0mvPD_m8QtkpcH7QsUsn0pfPRhmKPI3KnsVhzZ0ECVBJCBpz2KdarhLSGIh6j_z8CUy6_z1f6ONY6Bj9DDL7oDOqnv9UDQfMoVLDSFAeAdDDE5LSvX1J7-vhATXBO1zZ7Hyi1BHxvr5y-gzbA9O__kV2-COxiTf0JNFS2n6Ywt4uI-TCQuqpKF0slDyui9yXPk8gQkL6VZzUWGykVTYhafYXN9Le Kiiskinen, T: Feeding whole grain with pelleted diets to growing broiler chickens decreases. Therefore the addition of wheat ap- parently tends to reduce the weight gain of broilers (Chwalibog and Eggum 1986, Petersen 1990, Elwinger et al. 1992, Jensen 1992). If the use of whole wheat is cautious or the nutrient contents of the complete diet is raised, the growth rate is similar to thatof the controls (Tiller 1989, Covasa and Forbes 1994, Ristic et al. 1994). Other feeding systems which include the use of whole grain are choice feeding and sequential feeding. These methods base on the use of a spe- cial balancer diet which in choice feeding sys- tems is provided with whole grain ad libitum in separate feeders. In sequential feeding time-lim- ited ad libitum access to whole grain alternates with a balancer diet. Choice feeding of broilers has been studied extensively using whole wheat but it has not been applied in practice because there is a risk ofimbalanced selection of the com- ponents, and the system requires extra equip- ment. Forbes and Covasa (1995) concluded that birds need a period of learning or adjustment to choice feeding. However, the life of a broiler may be too short for this. According to Gumming (1994) the learning period is 7-10 days for chickens, broiler chicks needing a longer period than layer-type chicks. Sequential feeding could be easier to apply in practice, but research into this regimen has been very limited. The length of the feeding period is important. Rose et al. (1995) reported the highest growth rates in the 8-h periods. Mixtures of crumbled or pelleted concentrates and whole grain have been studied previously but the results were not very encour- aging (Kiiskinen 1992). The objective of the present study was to examine feeding of whole grain mixed with a complete diet or with a spe- cial balancer diet in order to increase the pro- portion of grain and to replace part of the wheat with barley. Material and methods Ross broiler chicks were kept in floor pens (4 m 2) in a temperature controlled windowless room Table 1.Feeding regimens in Trial 1. Age of bird Group days 1 2 3 4 5 1-7 S S S S S 8-11 S S SW 95:5 S S 12-16 G SW 90:10 SW 90:10 GW 90:10 SWP 80:20 17-21 G SW 85:15 SW 85:15 GW 85:15 SWP 80:20 22-28 G SW 80:20 SW 80:20 GW 80:20 SWP 80:20 29-35 G SW 75:25 SW 75:25 GW 75:25 SWP 80:20 36-38 F SW 70:30 SW 70:30 GW 70:30 SWP 80:20 S = starter, G = grower, F = finisher, SW = mixture of a pelleted starter and whole wheat, GW =mixture of a pel- leted grower and whole wheat, SWP = pelleted mixture of a starter and wheat meal under a daily light period of 23 h. Peat was used as litter material. Each pen contained 60 sexed birds (15/m2) which had free access to feed and water. Half of the pens contained male birds and the other half females. The treatments were al- lotted between the successive pens containing the same sex. Three trials were conducted. Trial 1 included five treatment groups with the feed- ing regimens shown in Table 1. The industrial complete diets which were used either as the only feed (Group 1, control) or mixed with whole wheat (Groups 2-4) were based on soybean meal, pea meal, wheat, barley and oats. According to the declarations, the starter diet contained crude protein (CP) 23.0%, metabolizable energy (ME) 12.0 MJ/kg, lysine 1.4% and methionine 0.6%. The corresponding values for the grower diet were 20.0%, 12.5 MJ/kg, 1.2% and 0.5%. All birds, excluding those of group 3, were given the same crumbled starter diet (S) up to the age of 11 days. Group 3 was fed with the starter diet up to the age of one week. Thereafter groups 2 and 3 were given a mixture of pelleted starter diet and whole wheat (SW) and group 4 a mix- ture of grower pellets and whole wheat (GW). The proportion of whole wheat was gradually increased up to 30% (Table 1). Group 5 served, in fact, as a second control which was given a pelleted mixture of the starter diet and ground wheat in a proportion of 80:20 (SWP). 168 AGRICULTURAL AND FOOD SCIENCE IN FINLAND Vol. 5 (1996): 167-175. In Trial 2, all birds were fed the same indus- trial crumbled starter diet during the first 11 days. Thereafter the four treatment groups were fed according to the following plan; Group 1 A pelleted grower diet on days 12-37 (control) Group 2 Mixtures of pelleted balancer diet (BA) and whole wheat (W) in the following proportions: BA:W days 12-18 80:20 days 19-28 70:30 days 29-37 60:40 Group 3 BA+WBI mixture of whole wheat (70%) and barley (30%) as BA:W Group 4 BA+WB2 (W:B 50:50) as BA:W In Trial 3, the birds were fed the same pelleted starter diet for the first 11 days. The grower diets for the three treatment groups were as fol- lows: Group I A pelleted grower diet on days 12-38 (control) Group 2 BA+W in the following proportions: days 12-18 70:30 days 19-29 60:40 days 30-38 50:50 Group 3 BA+WB2 (50:50) in the same proportions as BA:W The pelleted starter, grower and balancer diets were manufactured in the feed mill of the Agricultural Research Centre of Finland, and their compositions are shown in Table 2. The number of replicates (pens) for a treat- ment was 6, 8 and 12 in Trials 1, 2 and 3, re- spectively. The live weight of chicks was meas- ured as a total weight per pen at one day, 11 days and 37-38 days of age. Feed consumption was measured between the weighings. Total slaugh- ter weight and mortality per replicate were re- corded. Abdominal fat pad, including gizzard fat and gizzard, was removed and weighed for 24 female birds per treatment in Trial 1, for 16 fe- males per treatment in Trial 2 and for 20 male birds per treatment in Trial 3, excluding group 3 in Trial 1. In addition, six carcasses (3 males, 3 females) per treatment (1,2 and 4) in Trial 1 were taken in the slaughter house for determining the fat content of thigh and breast meat. Subcutane- ous fat was included in the meat samples. The fat content of the meat samples was determined by eluting the fat with dichloromethane-meta- Table 2. Composition of the experimental diets in Trials 2 and 3. Ingredients g/kg Trial 2 Trial 3 Grower Balancer Grower Balancer Fish meal 40 60 Soybean meal 210 310 270 460 Wheat 300 100 300 230 Barley 300 320 300 220 Oats 92 130 70 Plant oil 30 41 30 40 Limestone 10 14 9 13 Dicalc.phosphate 10 14 14 24 Salt 3 4 3 5 Premixes 5 7 4 X Methionine add. 0.5 0.7 0.8 1.5 Calculated MEMJ/kg 12.0 11.8 11.8 11.4 Crude protein g/kg 200 240 200 260 Ca g/kg 8.8 12.2 8.1 12.7 Pavailable g/kg 4.0 5.3 4.0 5.9 Methionine g/kg 4.2 5.1 4.0 5.7 Lysine g/kg 10.9 14.1 10.3 15.3 nol according to the method of Maxwell et al. (1980). At the end of Trial 2, litter samples near the feeders were taken from six pens per treat- ment for dry matter determination. In statistical analysis the analysis of variance was applied using a SPSS program. The comparisons between treatments were performed using Tukey’s test (Steel and Torrie 1960). Results and discussion The analyzed crude protein (CP) content for the starter and grower diets of Trial 1 were 225 and 204 g/kg, respectively (Table 3). The CP of the corresponding whole wheat containing diets de- creased to 192 (SW) and 181 g/kg (GW) at the end of the growing period. According to the CP analysis of feed remains, birds did not select between pellets and whole wheat. In Trial 2, the analyzed CP for the grower was 209 g/kg and that of the balancer 248 g/kg. In the BAW diets 169 AGRICULTURAL AND FOOD SCIENCE IN FINLAND Kiiskinen, T: Feeding whole grain with pelleted diets to growing broiler chickens Table 3. Analysed crude protein (CP) content in the diets, grain and feed remains (in parentheses). Diet (grain) Trial 1 Trial 2 Trial 3 CPg/kg" CPg/kg" CPg/kg" Starter (S) 225 260 222 Grower (G) 204 209 202 Balancer (BA) 248 252 Wheat (W) 125 126 124 Barley (B) 140 126 S:W proportion BA:W BA:W 90:10 215(220) 80:20 229(231) 70:30 225 80:20 207(206) 70:30 212(220) 60:40 200 70:30 192(197) 60:40 198(211) 50:50 189 G:W proportion BA:WB1 (W:B 70:30) 90:10 194(196) 80:20 223(232) 80:20 188(185) 70:30 214(225) 70:30 181(184) 60:40 198(214) BA:WB2 (W:B 50:50) BA:WB2 80:20 220(230) 70:30 220 70:30 211(225) 60:40 205 60:40 204(217) 50:50 189 11 88% dry matter the CP decreased to 198-204 g/kg at the end of the trial. The birds apparently ate slightly more grain than BA pellets because the CP for feed remains was 10-15 g/kg higher than that of the corresponding diet. The proportion of the re- mains was 10-15% of the given feed and so the changes in the supply ofnutrients were small and insignificant. The grower and the balancer diets of Trial 3 contained CP 202 and 252 g/kg, re- spectively. The CP content of the BAWG diets dropped to 189 g/kg during the last week. The calculated proportion of whole wheat was around 20% of the total feed consumption (Trial 1). Those birds which were given the SW feeding regimens consumed feed 7 g less per day (P<0.05) than the control birds (Table 4). Also groups 4 (GW) and S(SWP) which were fed a pelleted mixture of the starter and wheat meal ate less (P<0.05) than the control group. This was apparently the main reason for the 3-5% lower growth rates of the broilers given wheat in the diet. Groups 3 and 4 differed significantly (P<0.05) from the control group. However, the weight gain of the wheat - fed broilers, can be regarded as satisfactory. Also the slaughter weights of the wheat - fed groups de- creased by 1-4% and there was a significant (P<0.05) difference between the GW and the control groups. Compared with the control and the GW feeding treatments, each SW feeding regimen improved significantly (P<0.05) the feed efficiency (FCR) and the FCR of group 2 was significantly (P<0.05) better than that of group 5 which was given ground wheat in the pellets. This implies that whole wheat feeding has a beneficial effect on the digestion, appar- ently due to the enlargement of the gizzard. It seems that better results can be achieved when whole wheat is used with the starter pel- lets than with the grower pellets. This is under- standable, because the starters contain higher concentrations ofseveral nutrients (protein, min- erals, vitamins) than the growers and the effect of dilution with whole wheat is not so marked. This is clearly shown in the calculated total in- takes per bird (Table 5). The CP consumption of the GW birds was 570 g and that of the SW birds 607-608 g. The uptake of methionine was 13.4 g 170 AGRICULTURAL AND FOOD SCIENCE IN FINLAND Vol. 5 (1996): 167-175. Table 4. Effects of whole wheat feeding in Trial 1. Group 1 2 3 4 5 SEM2) Significance21 Grower diet" Control SW SW GW SWP Final body weight 2022b 1972“b 1959“ 1939a 1988ab 25.8 ** Weight gain 12-37 d 1725” 1678ab 1657a 1639a 1688ah 24.5 ** Slaughter weight g 1325b 1294ab 1300ab 1272“ 1306ab 18.3 ** Feed intake 12-37 d g/bird/d 115c 108“ 108“ 110“b 112b 1.1 *** FCR 12-37 d3 ' 1.89d 1.83* 1.84“b 1.88cd 1.87bcd 0.010 *** 1-37 d 1.80d 1.74“ 1.74“b 1.78““ 1.78“ 0.009 *** kg feed/kg slaughter weight 2.73c 2.63“b 2.61“ 2.7I c 2.69bc 0.013 *** Mortality % (12-37 d) 3.8 3.6 2.7 2.5 3.1 0.37 NS Gizzard weight g (females) 18.9“ 26.9b - 27.5b 17.2“ 0.52 *** %oflivewgt 1.10“ 1.64b - 1.66b 0,98* 0.033 *** Abdominal fat g (females) 47.1 b 37.6“ - 45.0b 46.7b 1.12 * % of live wgt 2.69b 2.26“ - 2.71 b 2.66“ b 0.058 * Carcass fat % Thigh males 9.38b 7.33“ - 9.82b - 0.478 * females 10.93 10.53 - 13.24 - 0.621 NS average 10.16b 8.93“ - 11.53b - 0.505 * Breast males 4.10 2.99 - 4.44 - 0.283 NS (P=0.06) females 4.69 4.82 - 5.74 - 0.224 NS average 4,40“b 3.91“ - 5.09b - 0.232 * 11 SW = starter + whole wheat, GW = grower + whole wheat, SWP = pelleted starter (80%) + wheat meal (20%) 21 SEM = standard error of mean, * P<0.05, ** P