Mash Diet Research Articles

Time structure of behavioral patterns related to feed pecking in chicks

Nonrandom time patterns of pecking acts by 16 chicks were detected using the software Theme during three videotaped pecking sessions (M, C, and A). At 15 days of age pecking session, M (mash) was recorded when chicks ate a mash diet. Pecking session C (change) at 16 or 17 days of age was recorded immediately after the change of the diet to pellets presented either as regular cylinders (P) to eight chicks, or as semiovoid (Po) to eight other chicks. Pecking session A (adapted) was recorded 5 or 6 days after adaptation to P and Po. Successful (consumatory) pecks were 72%, 52%, and 61% of all pecks for sessions M, C, and A, respectively. The head of the chicks remained in a steady position between two consecutive pecks for a longer period during C (65% of the time) than M and A (54%). During C, the pecking rate was less for P (0.54 pecks/s) than for Po (0.79 pecks/s). Two consistent time patterns involving four acts frequently observed were: head rotation (or exploratory peck)⇒head in steady position⇒consumatory peck⇒head in steady position with jaw movements. Time intervals within a pattern were stable throughout sessions. However, the proportion of synchronized (included in a pattern) vs. nonsynchronized (not included in a pattern) acts decreased immediately after the change of feed form (session C). These results suggest that pecking at feed is composed of two distinct sets of acts: consistently organized patterns little affected by the form of the pecked particles and nonsynchronized acts that may be involved in sensory information.

Test for physiological limitation to nutrient assimilation in a long-distance passerine migrant at a Springtime stopover site.

During northward migration, blackcaps arrive at stopover sites in Israel's Negev Desert with reduced masses of organs that are important in food digestion and assimilation. Blackcaps that stay to refuel (largely on fruits) do not gain mass rapidly until after 3 d at the stopover site. We hypothesized that (1) it may take several days to rebuild these reduced organs, (2) during this recovery interval high feeding rates might not be possible, and (3) this could be the basis for the absence of immediate body mass gain in blackcaps at stopover sites. To test predictions from this hypothesis we used an established fasting protocol to create a group of blackcaps with reduced intestinal and liver mass compared with ad lib. fed controls. Migrants were captured and caged in the laboratory, where they were habituated to a fruit mash diet for 8 d. One experimental group was then fasted 2 d, one was fed at a restricted level (one-third ad lib. food intake) for 4 d, and one was held as ad lib.-fed controls. The fasted and restricted birds were then allowed to feed again ad lib. Birds that were experimentally fasted progressively increased their daily assimilation rate and achieved the highest rate (one-third higher than controls) 3 d after the end of their fast. Birds that were restricted achieved high rates immediately once ad lib. food was provided. Increased assimilation rate was achieved via hyperphagia and not increased assimilation efficiency. The response of the fasted birds supports the hypothesis that there may be physiological constraints to the rate of refueling during migratory stopover.

Recovery responses of chick intestinal villus morphology to different refeeding procedures

Recovery responses of intestinal villus height and fine structure on the villus apical surface to different refeeding procedures were compared at refeeding 3 or 24 h after 3-d of feed withdrawal from chicks. After 3-d of fasting, 45-d-old male White Leghorn chicks (Gallus gallus domesticus) were refed rice bran (RB) (CP, 14.8%; ME, 3,170 kcal/kg), conventional grower mash diet (CG) (CP, 18.2%; ME, 2,853 kcal/kg), or ground CG (GG). During the experimental period, birds were given access to diets and water ad libitum. After the end of each experimental period, the duodenum was fixed and examined by light and scanning electron microscopy for morphological changes in the villi. Duodenal villus heights of chicks fasted for 3 d were significantly decreased compared with control chicks fed ad libitum. Villus heights were significantly increased after a 3-h refeeding, and the villi of the GG-refed group were significantly higher than RB and CG. When compared with villus heights at the 3-h refeeding, the RB-refed group showed no changes after a 24-h refeeding, but the CG and GG groups had significantly increased villi heights. Villi heights in GG groups were significantly higher than in the CG groups. Dietary effects on cell area and cell mitosis numbers were similar to those observed for villus height. The surface of the duodenal villi apices of control birds fed ad libitum revealed a clear cell outline, cell protuberances, and cell extrusion into the lumen. After 3-d fasting, cell outlines became faint, and protuberances and extrusion of cells disappeared. After refeeding for 3 h, clear cell outlines were again apparent in all groups. In GG-refed chicks, larger cell outlines and protuberated cells were found as conspicuous morphological features. Similar observations were made at the 24-h refeeding. These morphological findings suggest that chickens that were on feed withdrawal benefit from ad libitum refeeding of a powdered diet that is nutritionally complete for rapid recovery of digestive function.

Efeito do nível de trigo na dieta, do percentual de grãos germinados e da forma física da ração sobre o desempenho de frangos de corte

RESUMO - O objetivo deste trabalho foi determinar o melhor nível de substituição do milho por trigo, com 0 e 9% de grãos germinados (GG) em rações para frangos de corte. Rações fareladas (RF) na fase inicial (1 a 21 dias), trituradas (RT) na fase de crescimento (21 a 35 dias) e peletizadas (RP) na fase final (35 a 42 dias) foram usadas. Foi usado delineamento experimental em blocos casualizados, com cinco tratamentos e 12 repetições de 26 aves, na fase inicial, e 10 tratamentos e seis repetições de 26 aves, nas fases de crescimento e final. Os tratamentos foram: T1 - dieta à base de milho e farelo de soja (DMFS); T2 e T4 - substituição de 50% do milho da dieta T1 por trigo com 0 e 9% GG, respectivamente; e T3 e T5 - substituição de 100% do milho por trigo com 0 e 9% GG, respectivamente. O uso de RT de 21 a 35 dias e RP de 35 a 42 dias de idade aumentou o peso corporal (PC), ganho de peso (GP) e consumo de ração (CR). Contudo, a conversão alimentar somente foi melhor com a RT de 21 a 35 dias. O trigo com até 9,0% GG poderia substituir totalmente o milho em dietas de frangos de corte, quando comparadas à DMFS. Nas dietas à base de trigo e farelo de soja, o trigo com 0% GG determinou maiores PC, GP e CR que o trigo com 9% GG.

Effects of expanding and pelleting diets on finishing pigs fed from wet/dry feeders (2000)

Pigs fed pelleted and expanded diets from wet/dry feeders had 4.4% greater ADG and 7.9 % greater efficiency of gain than pigs fed a mash diet. Also, trends for greater efficiencies of gain occurred among pigs fed expanded pellets vs standard pellets and expandate vs expanded pellets.; Swine Day, Manhattan, KS, November 16, 2000

Effects of eating space and availability of water in feeders on productivity and eating behavior of grower/finisher pigs.

Three experiments were conducted to determine the effects of eating space and availability of water within feeders on the productivity and behavior of growing/finishing pigs. In Exp. 1, 12 commercial feeders were classified as being either single-space (SS) or multiple-space (MS), and either as dry (D) or wet/dry (WD), resulting in two SS-D, four MS-D, three SS-WD and three MS-WD models. Each model was evaluated using four pens of 12 pigs, which were fed a mash diet throughout the growing/finishing period (25 to 106 kg). Pigs were videotaped when they were approximately 40 and 80 kg in weight to determine eating behavior. The number of feeding spaces did not affect the productivity of the pigs, but the presence of water within the feeder resulted in increases in ADFI (P < .05) and ADG (P < .05) and a reduction in carcass lean (P < .05). Pigs eating from SS feeders spent 15% less time eating than those fed from two-space feeders (P < .05), and occupancy rate for feeding spaces was increased by 75% (P < .05). The WD feeders also resulted in a reduction (17%) in eatingtime compared to D models (P < .01), and occupancy rate for WD feeders was similarly reduced (P < .05). Pigs spent 16% less time eating when they weighed approximately 80 kg than when they weighed 40 kg (P < .01). In Exp. 2, rate of eating was determined during a short test on the same 12 feeder models for both small (48 kg) and large (90 kg) pigs. Large pigs ate faster than small pigs, but eating rate was not affected by feeding space or presence of water in the feeder. In Exp. 3, eating rate was determined for small amounts of dry or wet feed. Premixing water with the feed (1:1 ratio by weight) increased eating speed (P < .01). We concluded that 12 pigs can be fed from a single-space feeder without affecting productivity. The inclusion of water within a feeder decreases time spent eating, but it increases ADFI and ADG. When pigs are small, they spend more time eating, and feeder occupancy rates are higher than when they are large.

Feeding value of three categories of pea (Pisum sativum, L.) for poultry

AbstractThe nutritional value of different categories of peas was measured in mash or pelleted diets using adult cockerels. Twenty-five round and white-flowered peas (feed peas), 12 round and coloured-flowered peas and five wrinkled and white-flowered peas were used in mash diets. From the same batches, 11 feed peas, five coloured peas and four wrinkled peas were tested in pelleted diets.Mean apparent metabolizable energy (AME) values were 12·02, 11·35 and 10·50 MJ/kg dry matter (DM) for feed peas, coloured peas and wrinkled peas respectively in mash diets and 13·18, 12·72 and 11·63 MJ/kg DM for the same categories in pelleted diets.Mean starch digestibility was 0·905, 0·887 and 0·802 for feed peas, coloured peas and wrinkled peas respectively in mash diets and 0·985, 0·984 and 0·840 for these categories in pelleted diets.Mean protein digestibility was 0·788, 0·643 and 0·798 for feed peas, coloured peas and wrinkled peas respectively in mash diets and corresponding values for peas in pelleted diets were 0·855, 0·743 and 0·853.Pelleting thus had a positive effect on the nutritional value of peas and this improvement was all the more important because the AME and protein digestibility of the pea in mash diets was low.The nutritional value of feed peas for cockerels was not strongly correlated with chemical composition or to digestibility data obtained in the pig.

Production and egg quality as influenced by mash or crumbled diets fed to laying hens in an aviary system

Effects of feeding a crumbled diet compared with a mash diet on laying performance and egg quality of two hybrids of laying hens, a total of 3,204 birds, kept in an aviary system from 20 to 80 wk of age, were investigated. The two diets had the same composition and calculated nutrient content. Two hybrids, Lohmann Selected Leghorn (LSL) and SLU-1329 (a two-line cross of Leghorn x Rhode Island Red), were housed in six pens each of an aviary system with groups of 269 and 265 birds, respectively. There was a total of three replicates per treatment (diet x hybrid). Birds fed the mash diet compared with those fed the crumbled diet had a significantly higher proportion of misplaced eggs, inferior feed conversion ratio (FCR), and higher energy consumption per kilogram egg mass produced (collectable misplaced eggs included). The latter birds had higher body and egg weight, suggesting a higher nutritive value for the crumbled diet. Higher egg mass production and a more intensive yolk color were also found for the birds fed the crumbled diet compared with the mash diet. Hybrid affected production and egg quality traits the most. The LSL also showed significantly higher excreta DM compared with SLU-1329. Interactions between diets and hybrids were found regarding the proportion of misplaced eggs, dirty eggs, egg weight, and FCR. Some of the interactions may indicate other genetic and nutritional factors affecting bird performance in aviary systems more than is normally seen in cages.

Total tract and ileal nutrient digestibility of a diet fed as mash or crumbled pellets to two laying hybrids

Two diets, one fed as mash and the other as crumbled pellets, with the same composition and calculated nutrient content, were studied. Two hybrids were used, Lohmann Selected Leghorn (LSL) and SLU-1329 (a cross bred of Leghorn × Rhode Island Red-line). Chromium oxide was used as a digesta flow marker at the ileal level. Feed consumption was recorded during 5 days and excreta were collected quantitatively during this period. At the end of the trial the birds were sacrificed for crop and ileal content sampling. Significant interactions between hybrid and diet were found in ileal crude protein digestibility ( P < 0.05); LSL showed higher digestibility when fed the crumbled pellets than when fed the mash diet, whereas the results were the opposite for SLU-1329. This may indicate a difference in nutrient flow and absorption depending on genotype. At the total tract level, no differences of importance in nutrient digestibility between diets could be noted. Nonetheless LSL had drier excreta and higher total tract digestibility of organic matter ( P < 0.05) and crude fat, and also higher metabolisable energy ( P < 0.1), than SLU-1329. LSL also had higher concentrations of succinic acid in crop ingesta having 0.27 mg/g dry matter, compared with and 0.16 mg/g dry matter for SLU-1329 ( P < 0.05).

Performance and gastro-intestinal response of broiler chickens fed on cereal grain-based foods soaked in water

1. Two experiments were carried out to investigate the addition of 1.3 kg water per kg air-dry mash diets containing high proportions (600 to 700 g/kg) of ground cereal grains (wheat, barley or oats) on broiler performance and the structure and function of the gastro-intestinal tract. 2. Chicks at the age of 7 d were fed on the wheat-, barley- or oats-based diets in the dry or wet forms for 35 d. Food and water intakes were recorded daily while body weight was measured weekly. Two birds from each treatment were killed each week to measure gut size and the viscosity of gut contents. Tissue samples from various digestive segments were histo-morphologically examined to determine the thickness of tissue layers, size of tissue glands, villa heights, crypt depths and thickness of tunica muscularis . Crypt cell proliferation rate (CCPR) for each segment was also determined using a metaphase arrest technique. 3. The results from both experiments showed that wetting food significantly ( P <0.05) increased food intake, total water intake and body weight gain of broiler chickens. The body weight gains of birds were proportional to their food intakes so that the efficiency of food utilisation was similar for all treatments. Dry matter retention of food tended to increase in birds given wet food from 7 to 21 d but not thereafter, compared to the dry-fed birds. Although water intake from the water bottle was significantly ( P <0.05) reduced in birds given wet food, total water intakes from the water bottle plus that from food were significantly ( P <0.05) higher in the wet-fed birds than in the dry-fed birds. The ratio of total water to dry food intake was, however, similar in both feeding regimens. 4. The fresh empty weight of the gut was increased by wet-feeding while its relative weight to body weight and the length of gut was not affected by dietary treatments. Significantly greater development of the tissue glands in the proventriculus and gizzard was observed in the birds given wet food; this was associated with the reduced thickness of the muscular layer of these segments. An increase in villus height was also observed in duodenum, small intestine, caeca and colon of birds given wet food, compared to those given dry food. CCPR was significantly ( P <0.05) reduced by wet-feeding throughout the digestive tract. This was associated with a significant decrease in the mean viscosity of the gut contents and the concentration of volatile fatty acids (VFAs) in the caeca. 5. Wetting diets based on cereal grains caused a significant improvement in the performance of broiler chickens. The mechanism of the beneficial effects of wet feeding could be attributed to the decreased viscosity of gut contents; the greater development of the layer of villi in the digestive segments and the reduced CCPR in the crypts of the epithelium.

Effect of microbial enzyme supplementation on energy, amino acid digestibility and performance of pigs fed hulless barley based diets

Two experiments were conducted to investigate the influence of a microbial enzyme preparation on the digestibility and performance of starter-growing pigs fed hulless barley based diets. In the digestibility trial, eight pigs with an average initial body weight of 14.3 ± 0.4 kg initial liveweight were surgically fitted with steered ileo-cecal valve cannulas at the terminal ileum. Two hulless barley varieties (Condor and CDC Buck) were separately used as the dietary energy source (77.6%) with canola meal as the protein supplement (20%). Enzyme supplementation improved (P &lt; 0.05) the ileal dry matter (DM) digestibility by 15.2%, gross energy (GE) by 11.0% and protein by 7.6%. The average apparent ileal digestibility of the indispensable amino acids was improved by 6.9% (P &lt; 0.05), and of nonstarch polysaccharides (NSP) was improved by 90%. The total-tract digestibility of DM was increased by 6.2%, GE by 6% and crude protein (CP) by 9.4% (P &lt; 0.05). Enzyme supplementation tended to enhance digestion in the small intestine instead of the hind-gut as expected. In the growth performance trial, positive responses from enzyme supplementation were observed from both mash and pelleted diets fed to 48 pigs grown from 9 to 60 kg liveweight. The ADG was improved by 8.6% (P &lt; 0.05) and feed conversion by 8.7% (P = 0.09). Pelleting had no adverse effect on enzyme activity. The results demonstrated that the enzyme supplementation improved (P &lt; 0.5) nutrient utilization and performance of pigs fed diets containing hulless barley. Key words: Enzyme, hulless barley, digestibility, performance, swine

Effect of cultivar and environment on the feeding value of Western Canadian wheat and barley samples with and without enzyme supplementation

The feeding value ofnine wheat cultivars grown in replicate in three locations in each of two crop years, and 14 barley cultivars grown in seven locations over three crop years was tested with or without an appropriate commercial enzyme using a broiler chick bioassay. Four pens of six male broilers were fed mash diets containing 80% of the test cereal with or without enzyme from 4 to 17 d. Digestibilities were determined using an acid insoluble ash marker at 1.1% of diet. Significant intraclass correlation coefficients between duplicate wheat samples suggested a common effect of the location, but their low to moderate values suggested the presence of random variation or variation due to unique growing conditions within location. For both wheat and barley samples, the growing location affected the feeding value of the cereal grain and subsequent broiler chick performance. Durum wheat cultivars had higher feeding values than that of other wheat classes, both with and without enzyme supplementation, and the response to enzyme supplementation was low, likely reflecting a low level of soluble non-starch polysaccharides. The values of hulless barley cultivars were similar to those of hulled cultivars without enzyme, but the lower crude fibre in hulless barley resulted in higher feeding values when diets were supplemented with enzyme. The response to enzyme supplementation for both wheat and barley cultivars was dependent on the feeding value of the cereal grain without supplementation. Knowledge of variation in enzyme response could be used by feed manufacturers to determine the economic merit of supplementing with enzymes. Key words: Metabolizable energy, broilers, performance, wheat, barley, enzyme

Indigenous feed microflora and Salmonella typhimurium marker strain survival in poultry mash diets containing varying levels of protein

The effect of varying concentrations of different protein sources on the survival of a Salmonella typhimurium marker strain resistant to both novobiocin and nalidixic acid in nonsterile poultry mash diets was determined. A dry inoculum containing a primary poultry isolate of S. typhimurium was used to evaluate survival in mash containing one of two protein sources, soybean meal or meat and bone meal, at five concentrations (100, 150, 200, 250 and 300 g crude protein kg −1 mash) and stored at room temperature (21±1°C) for 56 days. In general, aerobic enumerations recovered from diets containing meat and bone meal were greater than those from diets containing soybean meal excluding day 0 and 56 ( P<0.05). During the 56-day period a reduction by approximately 0.5 log 10 colony forming units Salmonella g −1 mash was observed. The differences of Salmonella survival between soybean and meat and bone meal based diets was not consistent among 10 sampling points. No significant differences of either aerobic bacterial populations or Salmonella were observed for the five concentrations of protein for each source ( P≥0.05). However, large numbers of this organism survived at all protein concentrations well beyond typical storage times.

Hyperphagia in pre-fed rats following oral δ 9-THC

WILLIAMS, C.M., P.J. ROGERS AND T.C. KIRKHAM. Hyperphagia in pre-fed rats following oral Δ 9-THC. PHYSIOL BEHAV 65(2) 343–346, 1998.—Using a pre-feed paradigm, the effects of orally-administered Δ 9- tetrahydrocannabinol (THC) on low baseline levels of nocturnal feeding were assessed. Following 2-h access to a palatable wet mash diet at dark onset, adult male Lister hooded rats (Charles River) were treated with either sesame seed oil vehicle or Δ 9- tetrahydrocannabinol (0.063, 0.12, 0.25, 0.5, 1.0, or 2.0 mg/kg). One hour later, rats were allowed ad libitum access to standard chow, and intakes were monitored over the subsequent 24 h. Doses of 0.5, 1.0, and 2.0 mg/kg produced substantial hyperphagia during the first hour of testing. Subsequently, rats compensated for their overconsumption so that 24-h intakes were similar in all conditions. The data confirm anecdotal reports of the orexigenic actions of exogenous cannabinoids and suggest a critical role for endogenous cannabinoid systems in the regulation of appetite .

Metastatic mineralisation in brushtail possums (Trichosurus vulpecula) from Kawau Island

Aims. To describe the nature and incidence of metastatic mineralisation in brushtail possums (Trichosurus vulpecula) caught on Kawau Island. Methods. Wild-caught possums were individually housed in captivity over a 24-month period and fed a cereal-based mash diet. Possums that became debilitated were examined post mortem for evidence of metastatic mineralisation of the heart, major blood vessels and kidneys. Serum and aortic segments were collected from affected animals and were analysed for mineral composition. Non-debilitated animals and possums that were experimentally poisoned with cholecal- ciferol were examined as a comparison. Results. Fifteen of 42 possums (36%) captured on Kawau Island and housed in captivity were debilitated as a result of metastatic mineralisation of the walls of the aorta and/or of the kidney tubules, with four further possums having evidence of mineralisation when humanely killed. Phosphate and ammonium deposits were found in the aorta, and calcium deposits in the kidney tubules. Serum phosphorus and calcium levels were elevated in the debilitated animals. Similar lesions were found in only one of 288 possums captured from other North Island areas and housed in captivity over the same time period. Conclusion. Possums from Kawau Island appear to be more predisposed to metastatic mineralisation than possums from other areas of the North Island. The lesions observed in these possums were similar to those caused by cholecal- ciferol poisoning.

Effects of Aspergillus fumigatus phytase on phosphorus digestibility, phosphorus excretion, bone strength and performance in pigs.

Phytic-phosphorus has a very low bioavailability for monogastric animals and the non-utilized mineral contributes to the phosphorus (P) pollution problems. Phytases may ameliorate phytic-P antinutritive properties. However, phytases are very sensitive to the pelleting temperature commonly used for compound feed production and thus the challenge to produce a more thermostable phytase is very important. Pure Aspergillus fumigatus phytase (AFP) has the ability to refold into a native-like fully active structure after heat denaturation (20 min at 90 degrees C). The aim of the present work was to evaluate in vitro (in feed) and in vivo in young and in growing-finishing pigs the effects of AFP included in the feed at a level of 500 U/kg. Feed supplementation with AFP resulted in an in vitro phosphorus release of about three times higher than that obtained from the basal diets, irrespective of the pH value used for the determination (5.5 or 7). When the supplemented feed was steam pelleted at about 84 degrees C, the free P obtained after incubation at pH 5.5 represented 53% on an average of that obtained from the corresponding mash diets. The phytic-P-rich diets systematically induced hypophosphataemia, hypercalcaemia and hyperphosphatasaemia. The normal blood levels of P, Ca and alkaline phosphatase were restored by AFP. P apparent digestibility was significantly higher for the AFP diet (52.8 versus 30.8%). The improvement in Ca digestibility was not statistically significant. In all three in vivo experiments, AFP significantly decreased the P concentration in faeces (between 13 and 33%) as well as increased the growth rate and decreased the feed conversion ratio. Bone strength was significantly higher in the growing-fattening pigs fed on the AFP diet.

The bio-availability of phosphorus from feed phosphates for broilers as influenced by bio-assay method, dietary Ca-level and feed form

The apparent retention of P from feed phosphates was investigated in two balance trials (experiments 1 and 3) using a nearly P-free basal diet and fed respectively as pellets and crumbles. Experiment 2 was a 3-factorial comparative bio-assay growth trial, involving 2688 male broiler chicks, in which a low-P mash diet (0.7 g/kg non-phytin P) was supplemented to P levels of 1.3, 1.9, 2.5, 3.1 and 3.7 g/kg from commercial monobasic calcium phosphate monohydrate (MCPh) Ca(H 2PO 4) 2 · H 2O, dihydrated dibasic calcium phosphate (DCPh) CaHP0 4 · 2H 2O and anhydrous dibasic calcium phosphate (DCPa) CaHP0 4. Asymptotic regression models were fitted to the response parameter toe ash-% to derive relative P bio-availability values for the feed phosphates. The effect of two Ca levels (9.1 vs. 10.5 g/kg in experiment 1 and 8.5 vs. 10 g/kg in experiment 2) on P utilization was also studied. The apparent P retention with the pelleted diet was on average 78.1, 74.2 and 63.6% respectively for MCPh, DCPh and DCPa and significantly different (LSD = 3.3%). The effect of Ca was not significant. With the crumbled diet the apparent P retention appeared to be distinctly higher, being 85.5 ± 1.9 and 82.3 ± 1.6 for MCPh and DCPh. The results suggest that apparent P retention is markedly influenced by diet form (hardness of the pellets) and that the results of the latter balance trial are more useful for the formulation of crumbled or mash diets. The relative bio-availability of P from MCPh, DCPh and DCPa, obtained in the comparative trial was respectively 100, 93 and 85. This ranking was comparable with the relative ranking based on the apparent P retention in the feed phosphates in the balance trials. The results from the three experiments suggest the use of relative P utilization values in diet formulation for broilers.

Effect of choice feeding on the performance of broilers

1. Male broilers from 21 to 56 d of age were fed their diet either mixed as pellets or mash, or as separate ingredients presented on a free‐choice basis, to determine whether feeding method affected growth, carcase composition or profitability to 56 d of age. 2. The 12 treatments were: 2 completely balanced diets fed as mash or pellets, 8 choice fed diets containing maize or sorghum as the energy source (whole or mash) and protein concentrate (pellets or mash) and 2 unbalanced mixed mash diets containing 50% grain (maize or sorghum) plus 50% protein concentrate. 3. For the choice treatments, one food, grain (maize or sorghum) or protein concentrate (mash or pellets), was placed in each feeder. Broilers fed the complete pelleted or mash diet received the diet in both feeders. Food consumption was recorded weekly. Broilers were weighed at 42 and 56 d of age. 4. There were no significant differences between treatments and the pelleted control diet with regard to body weight, food consumed, food efficiency, carcase ash, dressing percentage and mortality. 5. Choice fed broilers receiving the energy source as whole grains had larger gizzards while the higher protein diets (50/50) resulted in a higher carcase moisture and protein but lower carcase fat than the broilers fed the pelleted control diet. 6. The main advantage of choice feeding appears to be the economical savings of feeding whole grains as the energy source.

The effect of a wheat-fat-interaction on the efficacy of a multi-enzyme preparation in broiler chickens

The effect of different dietary combinations of wheat (0, 250 and 500 g kg −1) and fat (low, medium, high) on the efficacy of a commercial multi-enzyme preparation (Bio-feed + CT: BCT) was assessed in a balance trial with broiler chickens from 22 to 26 days of age using mash diets. Responses were measured in terms of excreta/feed( E/F)ratio, N-retention, fat digestibility and MEn-values. All balance parameters were to a variable degree influenced by the 3 dietary factors (wheat, fat and BCT). In addition, there were 2 interesting interactions, (1) the favorable effect of BCT on the balance parameters was only obvious in combination with wheat (directly proportional to the wheat level) and (2) the effect of fat supplementation on dietary MEn-content was variable and dependent on dietary wheat concentration (the curvilinearity was directly proportional to the wheat level). The MEn-content of wheat was clearly influenced by the 3 dietary factors: its inclusion level (−3.8% lower at 500 than at 250 g kg −1), dietary fat level (−2 and −4% at medium and high fat level, resp.) and BCT-supplementation (varying from +4.9 to 9.4%). The MEn-equivalence of BCT was quite variable, varying from about 110 (at 0 g kg −1 wheat) to 1020 MJ/kg (at 500 g kg −1 wheat combined with either medium or high dietary fat level). The required wheat/BCT ratio should be adapted to the dietary wheat concentration (250 versus 500 g kg −1) or not. For a constant MEn-increase of wheat (e.g. +8%) the respective ratios were 702 and 1171, but for the same target MEn-value of wheat, this ratio was about 715 and was largely unaffected by dietary wheat concentration.

Whole canola/pea and whole canola/canola meal blends in diets for broiler chickens 2. Determination of optimal inclusion levels

Whole canola/pea (WCP, 1:1 wt/wt) or whole canola/canola meal (WCC, 3:1 wt/wt) were heat-processed using a commercial pellet mill prior to incorporation in broiler starter (0–20 d) and finisher diets (20–40 d). The pelleted blends readily disintegrated in the preparation of the mash diets. Body weight gain of broilers (0–40 d) fed WCP (0, 10, 20, or 30%) or WCC (0, 5, 10, or 15%) declined linearly with level of dietary inclusion (P &lt; 0.01). Feed intake declined curvilinearly (P &lt; 0.01) with both blends, with lower intake most apparent at the higher inclusion levels. Feed/gain increased for broilers fed WCP or WCC (P &lt; 0.01). Overall broiler mortality declined incrementally with inclusion of WCP (P &lt; 0.07) or WCC (P &lt; 0.03) in the diet. Although there was no distinct limitation on the dietary inclusion levels of either blend, the low feed intake with broilers fed 15% WCC indicated that its level should not exceed 10% of the diet. Key words: Canola seed, canola meal, peas, broiler chickens