The establishment and persistence of food preferences in lambs exposed to selected foods

Our study determined whether lambs' food preferences developed as a result of exposure to specific foods early in life and whether the presence of the mother affected the development of dietary preferences. In the first experiment, lambs were fed wheat (W) and mountain mahogany (MM) (Cercocarpus montanus) from 50 to 110 d of age. After exposure to W and MM, lambs preferred (P less than .05) W when offered with barley (B) but did not prefer (P greater than .05) MM when offered with serviceberry (SB) (Amelanchier alnifolia), probably because lambs were reluctant to eat mountain mahogany during exposure. Persistence was determined by dividing lambs exposed to W or MM into four groups: 1) continued exposure to W (MM); 2) exposure to B (SB); 3) no further exposure; and 4) exposure to W + B (MM +SB). Preferences for wheat persisted (P less than .05) regardless of the second exposure. In the second experiment, lambs were exposed to W (MM) either alone or with their mothers. Persistence was determined after 21 d of exposure to B (SB). Lambs preferred (P less than .05) W and MM whether they were exposed alone or with their mothers. However, preferences persisted longer in lambs exposed with their mothers. Finally, lambs exposed to either SB or MM with their mothers were later allowed to choose between SB or MM. Lambs strongly preferred (P less than .05) the shrub to which they were exposed early in life.     

Diet selection by growing lambs offered whole barley and a protein supplement, free choice: Effects on performance and digestion

Feeding whole barley and a protein supplement at choice to early weaned lambs (15 kg initial weight) was studied in four experiments. In a first experiment whole barley and a pelleted soybean meal-based supplement (348 g crude protein (CP)/kg dry matter (DM)) were given either at choice (CH) or mixed in a 75 / 25 ratio (M) and compared to a pelleted compound feed containing the same ingredients and supplemented with barley straw (C). The effect of allowing free access to straw in the CH treatment (CHS) was tested in a second experiment. Rumen fermentation was also studied in six lambs per treatment slaughtered after the growing period, and digestibility and allantoin excretion were determined in other four lambs per treatment. In Experiments 3 and 4 supplements containing 253–264 (L), 341–329 (M) and 424–427 (H) g CP/kg DM were offered at choice with whole barley to lambs penned individually (Experiment 3) or in a group (Experiment 4) and diet selection and lamb performance were recorded.

The protein supplement was selected in proportions of 0.28 and 0.34 (S.E. 0.021) of concentrate intake with treatments M and CH (Experiment 1) and 0.45 and 0.52 (S.E. 0.033) with treatments CH and CHS (Experiment 2). The concentration of rumen ammonia increased (P < 0.05) to 28 and 56 (S.E. 8.6) mg/l compared to 12 mg/l in treatment C. Rumen pH also increased (P < 0.001) from 4.95 to 5.48 and 5.60 (S.E. 0.080) with treatments CH and CHS while the concentration of volatile fatty acids and the acetate to propionate ratio tended to decrease (P < 0.1). Organic matter digestibility and allantoin excretion were higher with whole barley feeding (0.82 vs. 0.75 (S.E. 0.18) and 13.1 vs. 7.7 (S.E. 1.06) mmol/d) but decreased with straw supplementation (0.78 and 10.2 mmol/d). Daily weight gain of male lambs (but not of females) tended (P = 0.08) to be higher with whole barley than with the compound feed due to higher concentrate intake (P < 0.05), which was also depressed by straw supplementation of whole barley reducing the rate of gain (P = 0.06). Incidence of hyperparakeratosis and ulceration of rumen wall was high with all treatments (0.80 and 0.36) but papillary clogging was less frequent (P < 0.01) with whole barley (0.16) than with the compound feed (0.70) and tended (P = 0.01) to be reduced by straw supplementation. In Experiments 3 and 4 the proportion of protein supplements selected ranked in reverse order to their CP content, resulting in diets of similar CP concentration (180–200 g/kg DM). It is concluded that choice feeding of whole barley may be a practical alternative that offers some advantages over conventional compound feeding of growing lambs.     

淀粉酶和纤维素酶对玉米-豆粕型日粮的体外消化研究

本试验旨在通过透析袋体外酶解的方法,研究淀粉酶和纤维素酶对玉米-豆粕型日粮还原糖生成量、干物质和粗蛋白质体外酶解效果的影响。试验采用单因子试验设计,设对照组,试验1、2、3、4、5组,其中试验组淀粉酶的添加浓度分别为0.4、0.8、1.2、1.6、2.0U/g,试验组纤维素酶的添加浓度分别为1.0、2.0、3.0、4.0、5.0U/g,每个添加水平分别设5个重复。试验结果表明:淀粉酶添加浓度由0.4U/g提高至2.0U/g时,试验1、2、3、4组还原糖生成量较对照组分别提高0.22%、26.46%、6.99%、3.93%(二次,P<0.05),试验5组还原糖生成量下降1.72%(二次,P<0.05);试验1、2、3、4、5组干物质酶解率较对照组分别提高3.67%、4.58%、4.68%、5.69%、6.13%(线性,P<0.05)。纤维素酶添加浓度由1.0U/g提高至5.0U/g时,试验1、5组还原糖生成量相较于对照组分别降低1.31%、1.82%(二次,P<0.05),试验2、3、4组较对照组分别提高8.05%、32.76%、19.70%(二次,P<0.05)。以干物质酶解率为评价指标,淀粉酶添加的最适浓度为0.8U/g,以还原糖生成量为评价指标,淀粉酶和纤维素酶的最适添加浓度分别为1.05U/g和3.08U/g。     

Ryegrass-based diet and barley supplementation: partition of nitrogenous nutrients among splanchnic tissues and hind limb in finishing lambs

Splanchnic metabolism of nitrogenous nutrients and their uptake by the hind limb were studied in finishing lambs receiving ryegrass harvested at grazing stage with or without barley supplementation. Six multicatheterized lambs (40.2 +/- 1.5 kg) were fed with frozen ryegrass (RG) at 690 kJ of ME intake (MEI) x d(-1) x BW(-0.75) and 20.8 g of N intake (NI)/d successively without and with barley supplementation (RG + B), according to a crossover design. Barley supplementation represented 21% of DM intake and increased the MEI and the NI by 32 and 24% respectively, (P < 0.01). In the ruminal fluid, barley increased acetate and butyrate concentrations by 21.2 and 49.6%, respectively (P < 0.04), without any effect on the ammonia concentration. Consequently, the net portal appearance (NPA) of ammonia was not modified, but the NPA of total amino acids (TAA; +38%) and nonessential amino acids (NEAA; +45%) was increased (P < 0.05) by barley supplementation. Taken individually, the NPA of the essential amino acids (EAA) was increased for isoleucine (+32%; P < 0.05), threonine (+151%; P < 0.03), and lysine (+26%; P < 0.06), with no effect for the other EAA. In contrast to what was observed at the PDV level, no significant alteration in the net hepatic amino acid flux was observed for TAA, EAA, NEAA, branched-chain amino acids (BCAA), urea, and ammonia after barley supplementation, showing a relatively minor role of the liver in the regulation of the supply of amino acids to the peripheral tissues. However, taken individually, the net hepatic uptake of some NEAA involved in gluconeogenesis and/or ureagenesis was altered with barley supplementation: the alanine uptake was increased by 44% (P < 0.05), aspartate + asparagine (asx) uptake was decreased by 18% (P < 0.01), and glutamate + glutamine (glx) release tended (P < 0.10) to be increased by 208%. With barley supplementation, NI increased by 5 g of N/d, and net splanchnic release increased by 4.63 g of N/d. Consequently, the additional dietary N supply (together with energy supply) was nearly exclusively available to peripheral tissues as AA-N (N as amino acids), but no strong effect of this additional supply of AA to the hind limb could be demonstrated in terms of net AA hind limb fluxes. Consequently, barley supplementation of a ryegrass-based diet increased the net AA release by the splanchnic tissues, with little effect on the AA net uptake by the peripheral tissues.     

Ryegrass-based diet and barley supplementation: partition of energy-yielding nutrients among splanchnic tissues and hind limbs in finishing lambs

Splanchnic metabolism of energy-yielding nutrients and their uptake by the hind limb were studied in finishing lambs receiving ryegrass harvested at grazing stage (ear at 10 cm) with or without barley supplementation. Six ruminally cannulated and multicatherized lambs (40.2 +/- 1.5 kg) were fed with frozen ryegrass (RG) at 690 kJ of metabolizable energy intake (MEI) x d(-1) x BW(-0.75) successively with and without barley supplementation (RG + B), according to a triplicated Latin square design. Barley supplementation represented 21% of DM intake and increased the MEI by 32% (P < 0.002). In ruminal fluid, barley supplementation increased the acetate and butyrate concentrations by 21.2 and 49.6%, respectively (P < 0.04), without modifying those of propionate. Thus, molar proportions of acetate and butyrate were not modified, and those of propionate tended (P < 0.06) to decrease from 26 to 23%. As a result, the net portal appearance of propionate was not modified. Net portal appearance of butyrate and beta-hydroxybutyrate increased (P < 0.03), and that of acetate was not modified. Consequently, hepatic uptake of butyrate increased and probably spared acetate from hepatic metabolism. The hepatic fractional extraction of propionate decreased (P < 0.03), whereas the net flux of lactate switched from a net release to a net uptake, suggesting an alteration in the contribution of gluconeogenic substrates to glucose synthesis without modification in net hepatic glucose release. As a consequence, barley supplementation increased net splanchnic release of acetate (P < 0.02), propionate (P < 0.001), and beta-hydroxybutyrate (P < 0.01) by 60, 157, and 78%, respectively. In addition, the net splanchnic release of insulin increased (P < 0.03) because of a decrease (P < 0.02) in its hepatic extraction. Despite those changes, the net uptake of nutrients by the hind limb was not modified and even decreased in the case of glucose (P < 0.02), suggesting a stimulation of lipogenesis in adipose tissues. Results from the present study suggested that supplementation of a ryegrass-based diet would likely have little effect on the orientation of muscle energy metabolism and on meat quality because the net uptake of nutrients by the hind limb was unchanged.     

Intake of lambs offered ad libitum access to one of three iso-caloric and iso-nitrogenous mixed rations or a choice of all three foods

Modern practices for finishing livestock typically involve offering a single uniform food to large groups of presumably similar animals in an attempt to increase efficiency. Nevertheless, differences in physiology and behavior still cause variations in performance that may precipitate biological inefficiencies by not appreciating the importance of differences among individuals, the capacity of animals to select foods that meet ever-changing individual needs, and the dynamic nature of a nutrient's value to an animal. We examined intakes of groups of lambs offered a single food or three foods differing only in their proportions of cereal grains: High, 70%; Medium, 50%; Low, 40%. Foods consisted of the same ingredients (barley, corn, sugar beet pulp, alfalfa, soybean meal, grape pomace, feather meal, wheat straw), had similar levels of metabolizable energy (ME) and crude protein (CP), and met NRC requirements. We hypothesized that intake and performance would be greater when animals had a choice of foods because high grain concentrations would not limit intake of individuals unable to process high amounts of energy from grain. In general, lambs offered a Choice of the three foods ate more, converted food more efficiently, and cost less per unit gain than lambs fed the High food (P < 0.05). Animals fed the Low or Medium foods were intermediate in their responses between these two extremes. Within Choice, preference for High, Medium, and Low shifted from the beginning (21 d) to the finishing (21 d) periods of the trial. Though lambs in the Choice treatment preferred Low > Medium and High in the beginning stage of the trial, their preferences became pronounced as we increased the amount of grain in each food during the finishing period (P < 0.05). Collectively, our findings suggest improved intake, rate of gain, and feed efficiency can result when animals are allowed to select their diets from biochemically complementary foods, possibly enabling them to realize greater benefits than typically thought from inexpensive forages. In addition, offering animals choices is an alternative to feeding uniform diets of rapidly fermented energy, a major cause of illness in feedlots.     

Effect of lablab and pigeon pea leaf meal supplementation on performance of goats fed a basal diet of haricot bean haulms

An experiment was conducted to evaluate the effect of lablab and pigeon pea leaf supplementation on feed intake, digestibility, weight gain, and carcass characteristics of goats fed a basal diet of haricot bean haulms. Thirty-two yearling intact male goats with an average initial body weight of 14.4?±?1.04 kg (Means ± SD) were assigned to one of the four treatments in a randomized complete block design. The dietary treatments were 17.5% lablab?+?17.5% pigeon pea leaf?+?63% wheat bran (T1), 35% pigeon leaf?+?63% wheat bran (T2), 35% lablab leaf?+?63% wheat bran (T3), and 88% wheat bran?+?10% noug seed cake (T4). In addition, all treatment diets contained 1 and 1% limestone. The feeding trial lasted for 90 days followed by 7 days of digestibility trial. Carcass evaluation was conducted at the end of the feeding trial. Final body weight ranged from 16.3 kg for T4 to 21.1 kg for T3. The total dry matter (DM) intake for T3 was higher (P?<?0.05) than T2 and T4. The total crude protein (CP) intake for T2 was greater (P?<?0.05) than T3 and T4. Goats supplemented with T3 diets had the highest (P?>?0.05) digestibility of DM, organic matter, and CP and attained the highest (P?<?0.05) average daily gain, the heaviest (P?<?0.05) hot carcass weight, and the highest (P?<?0.05) rib-eye muscle area than those supplemented with T1, T2, and T4 diets. In conclusion, 35% lablab leaf meal and 63% what bran (T3) were found to be a very promising supplement in sheep fed low-quality crop residues under the condition of the current experiment.     

Seasonal variations in the diet and food selection of the Algerian hedgehog Atelerix algirus

The Algerian hedgehog Atelerix algirus is an insectivorous species. However, the exact composition of its natural diet remains largely undetermined, especially in relation to seasonal variations in food availability. From March to November, we simultaneously analysed the composition of 180 hedgehog faecal samples and food availability in the Soumman Valley, Algeria to assess food selection in this species. The faeces contained 196 different prey species, of which 92% belonged to the class Insecta. The highest prey species diversity was found in the Coleoptera order (100 species recorded) and the highest species occurrence was found in Hymenoptera (65% of the prey items, mainly represented by the harvester ant Messor barbarus, a crop-ravaging species). This study shows that the Algerian hedgehog is mainly a generalist species with a diet that is strongly linked to food availability. However, seasonal variations were observed in prey selection, and a notable shift in food preference was observed during autumn. The exact nature of these changes in feeding behaviour remains to be investigated, notably in relation to changes in energy requirements of this species before hibernation, in terms of quantity and/or quality.     

Comparison of corn gluten meal and meat meal as a protein source in dry foods formulated for cats

OBJECTIVE: To compare the nutritional value of corn gluten meal (CGM) and meat meal (MM) as a dietary source of protein in dry food formulated for adult cats. ANIMALS: 8 healthy adult cats (4 males and 4 females). PROCEDURE: Diets containing CGM or MM as the main protein source were each fed for a 3-week period in a crossover study. Digestibility and nutritional balance experiments were conducted during the last 7 days of each period. Furthermore, freshly voided urine was obtained to measure urinary pH, struvite crystals, and sediment concentrations. RESULTS: Daily food intake and dry-matter digestibility were significantly higher for the MM diet. Fecal moisture content also was higher for the MM diet. Apparent nitrogen (N) absorption and N retention were higher for the MM diet, even when values were expressed as a percentage to account for differences in N intake. Urinary pH, struvite activity product, number of struvite crystals in urine, and urinary sediment concentrations were not different between diets. Retention of calcium, phosphorus, and magnesium was lower for the CGM diet, and cats lost body calcium and magnesium when fed the CGM diet. CONCLUSIONS AND CLINICAL RELEVANCE: Meat meal was superior to CGM as a protein source in dry foods formulated for cats, because dry-matter digestibility and N utilization were higher for the MM diet. In addition, net loss of body calcium and magnesium for the CGM diet suggests that mineral requirements increase when CGM is used as a protein source.     

Comparative effects of individual amino acid excesses when added to a corn-soybean meal diet: effects on growth and dietary choice in the chick

Six experiments were conducted with 8-d-old crossbred chicks to evaluate the effects of 4% excesses of DL-methionine (Met), L-phenylalanine (Phe), L-tryptophan (Trp), L-lysine (Lys), L-histidine (His), L-threonine (Thr), L-isoleucine (Ile), L-arginine (Arg), L-valine (Val) or L-leucine (Leu) on growth or dietary "choice" (i.e., self-selection) when added to 23% protein corn-soybean meal (C-SBM) diets. Arginine and His were supplied as the free base and Lys as Lys X acetate to avoid acid-base problems. In the growth studies, weight gain was reduced 92, 79, 53, 50, 47, 31, 29, 15, 9, 4 and 0% by additions of 4% Met, Phe, Trp, His, Lys, Tyr, Thr, Ile, Arg, Val and Leu, respectively. Improvements (P less than .05) in weight gain, feed intake and gain/feed occurred by addition of 1% Arg to the C-SBM diet supplemented with 4% excess Phe or Tyr. Addition of 1% Arg to the C-SBM diet supplemented with 4% excesses of most of the other amino acids also tended to improve performance, although diets imbalanced with Lys, Val or Leu did not respond to supplemental Arg. Self-selection studies revealed that chicks preferred the C-SBM diet containing 4% excess Lys over diets containing 4% excesses of Met, Thr, Arg or Trp. Moreover, chicks preferred diets with 4% excess Met, Thr or Arg over those containing an equal excess of Trp. When given a choice between the C-SBM diet and this diet supplemented with 4% Leu, chicks consumed similar quantities of both diets.     

Effect of diet composition and feed intake level on diet digestibility and ruminal metabolism in growing lambs.

Lambs (29 +/- 2.5 kg) were fed three diets at various intakes to determine whether diet composition or level of intake was reflected in changes in diet digestibility or ruminal fluid characteristics. In Exp. 1, a 90% concentrated, pelleted diet or a whole shelled corn diet with a pelleted protein supplement was fed at three levels of intake: ad libitum and 92.5 and 85% of ad libitum (n = 15). Exp. 2 compared the 90% concentrate diet with diets in which the energy density was diluted to 55 or 72.5% concentrate by including alfalfa hay as a possible method of restricting energy intake (n = 6). Lambs were adapted to diets for 13 d; feces were collected for 6 d and ruminal fluid was collected 0, 3, and 6 h after feeding on the day following fecal collection. Restricting intake in Exp. 1 did not affect DM digestibility or digestibility of CP or starch. Digestibility of ADF was increased (P less than .10) by restricting intake. Ruminal fluid pH, ammonia concentration and VFA concentrations were affected little by either restricted intake level. Digestibility of DM was 4% higher (P less than .001) and starch 5% higher (P less than .001) for the whole shelled corn diet than for the pelleted, high-concentrate diet. Ruminal pH of lambs fed the whole shelled corn diet was higher and fluctuated less than the ruminal pH of lambs fed the high-concentrate, pelleted diet. In Exp. 2, diet digestibility was reduced (P less than .01) and ruminal pH was increased (P less than .002) by addition of hay. Restricted feeding of lambs did not seem to increase diet digestibility or alter ruminal conditions.     

Evaluation of low-ash poultry meal as a protein source in canine foods

Eight mature female dogs (18.0 +/- 0.2 kg) were used in a replicated 4 x 4 Latin square experiment to determine the feeding value of low-ash poultry meal (PM) in a complete food fed to dogs. All foods contained graded concentrations of PM (10.4 to 32.5% DM), resulting in foods that were 10, 15, 20, and 25% CP. Daily DMI averaged 284 +/- 14 g/d. An increase in PM resulted in an increase in fecal moisture from 44.7 to 55.1% (linear; P < 0.01), and fecal DM output increased from 24.8 to 31.6 g/d (linear; P < 0.05). Ileal DM flow increased from 27.1 to 40.7 g/d (linear; P < 0.01). Small intestinal DM digestibility decreased from 90.4 to 86.1% (linear; P < 0.01) and total-tract DM digestibility decreased from 91.2 to 89.4% (linear; P < 0.01) as PM increased. Large intestinal DM digestibility increased from 8.4 to 21.1% with increasing PM (linear; P < 0.05). Fecal excretion of CP increased from 5.6 to 10.0 g/d (linear; P < 0.01) and ileal flow of CP increased from 6.9 to 15.6 g/d (linear; P < 0.01) as PM increased. Small intestinal CP digestibility was unaffected with treatment (P > 0.05). Large intestinal CP digestibility increased from 21.6 to 37.1% (linear; P < 0.05) with increasing PM. Total-tract CP digestibility increased from 81.0 to 86.6% (linear; P < 0.01) as PM increased. Arginine had the highest overall digestibility ranging from 88.5 to 91.3%, whereas cysteine had the lowest digestibility, ranging from 67.1 to 71.4%. These data indicate that PM is a highly digestible protein source for canine foods with inclusions of 10.4 to 32.5% of DM.     

日粮中添加大蒜粉对肉仔鸡生产性能和肉质的影响

选用240只长沙黄肉鸡,随机分为4组,对照组饲喂基础日粮,试验组在基础日粮中分别添加杆菌肽锌(20mg/kg)、1.5%和2%的大蒜粉,比较试验鸡的生产性能和肉质.研究结果表明:①日粮中添加1.5%和2.0%的大蒜粉可显著提高肉鸡的日增重、饲料效率和成活率(P＜0.05)及改善肉鸡的屠宰率和肉品质.②大蒜粉可替代抗生素杆菌肽锌对肉鸡起促生长和提高饲料效率的作用.     

Effects of supplementing different levels of sun-dried groundnut foliage on intake,apparent digestibility and nitrogen metabolism in cattle offered a basal diet of a mixture of rice straw and para grass

Eight male Cambodian yellow cattle, initial body weight (BW) 136 ± 11.9 (±SD) kg; age 20 ± 2.5 (±SD) months, were randomly allocated to treatments in a double 4 × 4 Latin square design to investigate the effects of different levels of crude protein (CP) from sun-dried groundnut (Arachis hypogaea L.) foliage (DGF) on feed intake, apparent digestibility and nitrogen metabolism. All animals were fed a basal diet of rice straw ad libitum and para grass (Brachiaria mutica) at 1% of BW. The DGF was offered as a supplement at 0, 1, 2 and 3 g CP/kg BW, denoted DGF0, DGF1, DGF2 and DGF3, respectively. The results showed that the intake of DGF contributed 0, 25, 34 and 42% of total dry matter (DM) intake. Rice straw intake decreased when DGF intake increased. Total intake of DM, organic matter (OM), digestible OM, ash, neutral detergent fibre and acid detergent fibre increased with increased level of DGF inclusion but did not differ for the two highest DGF levels. Total DM intake as proportion of BW increased from 2.3% in DGF0 to 2.8% in DGF3. Crude protein digestibility and nitrogen retention improved as DGF intake increased. Daily weight gain of DGF1 cattle was higher than DGF0 but was not further improved at the higher levels of DGF inclusion. Microbial protein synthesis and efficiency of microbial protein production in DGF1 did not differ from DGF0 but both measures were higher in DGF2 and DGF3. The responses were diminished at higher DGF inclusion so it is suggested that DGF supplementation at 1 g CP/kg BW may be the optimal level.

     

Changes in gastric contents in pigs fed a finely ground and pelleted or coarsely ground meal diet.

The objective was to characterize the change in stomach contents in relation to time after feeding between pigs consuming a restricted amount of a finely ground and pelleted (FGP) or coarsely ground meal (CGM) diet. Particular interest was placed on the concentration of organic acids and ammonia, the products of microbial fermentation. Thirty barrows were ranked by weight and assigned to a postfeeding time of 2, 4, 6, 8, or 12 h and either the FGP or CGM diet. Initiation and termination of the experiment were staggered over a 2-wk period. The treatment period was 42 d. Percentage of dry matter was higher (P<.01) in the stomach contents of pigs on the CGM diet. Concentrations of pepsin and protein were higher (P<.05) and ammonia tended to be higher (P = .10) in the proximal stomach of pigs fed the FGP diet. In contrast, concentrations of acetate and L-lactate were higher (P<.05) in the proximal stomach of pigs fed the CGM diet. All pigs on the CGM diet had stomachs that graded as normal on visual inspection. There was variable damage to the stomachs of pigs on the FGP diet. Measurement of chromium concentration in the stomach after an oral dose of Cr-EDTA clearly demonstrated the mixing that occurs between the proximal and distal stomach by 2 h after feeding in pigs consuming the FGP diet, whereas a gradient was maintained in pigs consuming the CGM diet. Thus, components normally secreted in the distal stomach return to the proximal stomach. These data show that components secreted in the distal region, such as acid and pepsin, may play a role in initiating damage to the stratified squamous mucosa. High concentrations of organic acids in the stomach of pigs on the CGM diet were not associated with damage to the stratified squamous mucosa in the esophageal region.