Sequential feeding using whole wheat and a separate protein-mineral concentrate improved feed efficiency in laying hens.

The effect of feeding nutritionally different diets in sequential or loose-mix systems on the performance of laying hen was investigated from 16 to 46 wk of age. Equal proportions of whole wheat grain and protein-mineral concentrate (balancer diet) were fed either alternatively (sequential) or together (loose-mix) to ISA Brown hens. The control was fed a complete layer diet conventionally. Each treatment was allocated 16 cages and each cage contained 5 birds. Light was provided 16 h daily (0400 to 2000 h). Feed offered was controlled (121 g/bird per d) and distributed twice (4 and 11 h after lights-on). In the sequential treatment, only wheat was fed at first distribution, followed by balancer diet at the second distribution. In loose-mix, the 2 rations were mixed and fed together during the 2 distributions. Leftover feed was always removed before the next distribution. Sequential feeding reduced total feed intake when compared with loose-mix and control. It had lower wheat (-9 g/bird per d) but higher balancer (+1.7 g/bird per d) intakes than loose-mix. Egg production, egg mass, and egg weight were similar among treatments. This led to an improvement in efficiency of feed utilization in sequential compared with loose-mix and control (10 and 5%, respectively). Birds fed sequentially had lower calculated ME (kcal/bird per d) intake than those fed in loose-mix and control. Calculated CP (g/bird per d) intake was reduced in sequential compared with loose-mix and control. Sequentially fed hens were lighter in BW. However, they had heavier gizzard, pancreas, and liver. Similar liver lipid was observed among treatments. Liver glycogen was higher in loose-mix than the 2 other treatments. It was concluded that feeding whole wheat and balancer diet, sequentially or loosely mixed, had no negative effect on performance in laying hens. Thus, the 2 systems are alternative to conventional feeding. The increased efficiency of feed utilization in sequential feeding is an added advantage compared with loose-mix and thus could be employed in situations where it is practicable.

Adaptation of wheat and protein-mineral concentrate intakes by individual hens fed ad libitum in sequential or in loose-mix systems.

1. Feed intake and performance of birds given sequential or loose-mix feeding was investigated from 19 to 42 weeks of age. A complete diet was fed as control (C). A balancer diet (50) was fed either sequentially (S50) or in a loose-mix (L50) with wheat. This diet was formulated to provide a similar nutritive value as C assuming a 50 : 50 diet and wheat intake. Another balancer diet (25) was fed sequentially (S25) or in a loose-mix (L25) with wheat. The diet was to provide a similar nutritive value as C assuming 75 : 25 diet and wheat intakes. In sequential feeding, only wheat was fed in the morning (4 h after lights-on) and the balancer diet in the late afternoon (4 h before lights-off). In the loose-mix treatment, a mixture of the two diets was fed throughout the 16-h daily light. Each treatment was given ad libitum to 25 birds in individual cages. 2. Birds fed on L25 had lower total feed intakes than those receiving C, S50 or S25. Protein intake was reduced with L25 compared to C, S50, S25 and L50. Metabolisable energy (ME) intake was, however, similar among all treatments. Egg production and weight were reduced with L25 compared to S50 and S25. Body weight (BW) was lowered with L25. However, there was high individual variation in all variables. 3. Feeding system (sequential vs loose-mix) had no effect on ME intake. However, the loose-mix treatment reduced feed and protein intake due to lower balancer diet intake. It also resulted in low egg production, egg and BWs compared to sequential feeding. The weights of pancreas and gizzard were heavier with sequential and loose-mix compared to the control. 4. The loose-mix treatment reduced egg-laying performance. Sequential feeding resulted in similar egg-laying performance to conventional feeding and thus could be used to advantage in situations where it is applicable.

Immunochemical studies on gastric and intestinal digestion of soybean glycinin and beta-conglycinin in vivo.

Two experiments were conducted to study gastric and small intestinal digestion of soybean glycinin and beta-conglycinin in preruminant calves fed milk replacers containing a mixture of skim milk powder and antigenic heated soybean flour. In experiment 1, duodenal passage of immunoreactive beta-conglycinin lasted for a much longer time after the morning meal than that of glycinin. Western blotting revealed the early abomasal outflow of glycinin subunits that associated nearly intact basic polypeptides to partially degraded acidic polypeptides. Intact beta-conglycinin was evidenced at most sampling times. In experiment 2, intact basic glycinin (M(r) = 21000) associated with partially digested acidic glycinin (7000 < M(r) < 25000) was demonstrated in ileal digesta up to 8-10 h after the meal. beta-Conglycinin immunoreactivity could not be evidenced by Western blotting in ileal digesta.

Is sequential feeding of whole wheat more efficient than ground wheat in laying hens?

The impact of sequential feeding of whole or ground wheat on the performance of layer hen was investigated using ISABROWN hens from 19 to 42 weeks of age. In addition, the effect of reduced dietary energy content of a complete diet was also investigated. Four treatments were tested. Whole wheat was alternated with a protein-mineral concentrate (balancer diet) in a treatment (sequential whole wheat: SWW), while another treatment alternated ground wheat (sequential ground wheat: SGW) with the same balancer diet. The control (C) was fed a complete layer diet conventionally. Another treatment (low energy: LE) was fed a complete diet conventionally. The diet contained lower energy (10.7 v. 11.6 MJ/kg) compared to the C. Each treatment was allocated 16 cages and each cage contained five birds. Light was provided 16 h daily (0400 to 2000 h). Feed offered was controlled (121 g/bird per day) and distributed twice (2 × 60.5 g) at 4 and 11 h after lights on. In the sequential treatment, only wheat (whole or ground) was fed during the first distribution and the balancer diet during the second distribution. Left over feed was always removed before the next distribution. The total feed intake was not different between SWW and SGW, but the two were lower than C (P < 0.05). Wheat intake was however, lowered with SGW compared to SWW (P < 0.05). Egg production and egg mass (EM) were not different between treatments. Egg weight was lower with SGW than with SWW (P < 0.05), but the two were similar to C. Body weight (BW) was lowered (P < 0.01) with SGW relative to SWW and C, SWW BW being also lower than the C one. The efficiency of egg production was increased (P < 0.01) with the SWW and SGW relative to the control. Birds fed LE had higher feed intake (P < 0.05) but they had similar egg production and EM compared to the two sequential treatments. The efficiency of feed utilization was also reduced (P < 0.01) with LE compared to SWW and SGW. It was concluded that sequential feeding is more efficient than conventional feeding. In addition, whole wheat appeared more efficient than ground wheat in terms of egg and BW.

Analytical criteria for predicting apparent digestibility of soybean protein in preruminant calves.

A series of experiments on the use of soybean as a protein source in milk replacers for veal calves was undertaken to determine the relationships between the physicochemical and antinutritional properties and apparent digestibilities of nine soybean products. Soybean provided between 58 and 71% of dietary CP, and skim milk or whey powder provided the remainder. Soybean products were analyzed for CP, native protein, aggregated protein, carbohydrate-linked protein, peptides, antitryptic activity, and immunoreactivity of lectin, glycinin, alpha-conglycinin, and beta-conglycinin. The apparent digestibility of N calculated for soybean protein varied between 59 and 84%. Simple linear correlations were significant between apparent digestibility of soybean N and concentrations of native protein, antitryptic activity, glycinin, alpha-conglycinin, and beta-conglycinin. However, only variation in antitryptic activity, alpha-conglycinin, and beta-conglycinin contributed significantly to an explanation for the variation in apparent digestibility of soybean N in a multiple linear equation. Under our experimental conditions, beta-conglycinin was the best predictor of digestibility of soybean N. Antitryptic activity became the best predictor when soybean products had no detectable beta-conglycinin.

Digestibility, blood levels of nutrients and skin responses of calves fed soyabean and lupin proteins.

Three milk substitute diets in which the protein was provided either by skim milk only (control diet) or mainly (71%) by a commercial soyabean or lupin concentrate (soyabean or lupin diet, respectively) were given to intact or ileo-caecal-cannulated preruminant calves. In vitro tests showed that both concentrates were partially proteolysed and had low antigenic and antitryptic activities. The low antigenicity was confirmed in vivo since none of the calves produced specific plasma antibodies against dietary proteins, and skin reactions following the injection of these proteins were minor. Postprandial plasma level of triglycerides was higher with the 2 legume diets, suggesting faster abomasal emptying of fat and probably protein. Apparent faecal nitrogen digestibility was lower (P < or = 0.05) with the soyabean and lupin diets than with the control diet (0.86, 0.88 and 0.95, respectively). At the ileal level, the differences were smaller and non-significant (0.90, 0.88 and 0.92) for nitrogen, but remained significant for valine and tyrosine with the soyabean diet, and for proline, valine, methionine, leucine and lysine with the lupin diet. However, the differences were small enough to conclude that proper denaturation of soyabean and lupin proteins by processes including partial hydrolysis can suppress their antigenicity and render them very digestible.