The ability of hens to regulate phosphorus intake when offered diets containing different levels of phosphorus

Understanding the evolution of nutritive taste in animals: Insights from biological stoichiometry and nutritional geometry

A major conceptual gap in taste biology is the lack of a general framework for understanding the evolution of different taste modalities among animal species. We turn to two complementary nutritional frameworks, biological stoichiometry theory and nutritional geometry, to develop hypotheses for the evolution of different taste modalities in animals. We describe how the attractive tastes of Na-, Ca-, P-, N-, and C-containing compounds are consistent with principles of both frameworks based on their shared focus on nutritional imbalances and consumer homeostasis. Specifically, we suggest that the evolution of multiple nutritive taste modalities can be predicted by identifying individual elements that are typically more concentrated in the tissues of animals than plants. Additionally, we discuss how consumer homeostasis can inform our understanding of why some taste compounds (i.e., Na, Ca, and P salts) can be either attractive or aversive depending on concentration. We also discuss how these complementary frameworks can help to explain the evolutionary history of different taste modalities and improve our understanding of the mechanisms that lead to loss of taste capabilities in some animal lineages. The ideas presented here will stimulate research that bridges the fields of evolutionary biology, sensory biology, and ecology.

Female Preference and Adverse Developmental Effects of Glyphosate-Based Herbicides on Ecologically Relevant Traits in Japanese Quails

Controversial glyphosate-based herbicides (GBHs) are the most frequently used herbicides globally. An increasing number of studies have identified GBH residues in soil, water, and even human food that may expose nontarget organisms including wildlife, livestock, and humans to health risks. After a heated debate, the European Union allowed the use of GBHs to continue until 2022, after which their risks will be re-evaluated. Thus, decision makers urgently need scientific evidence on GBH residues and their possible effects on ecosystems. An important, yet neglected, aspect is to assess whether animals show preference or avoidance for GBH-contaminated food, as it can influence the likelihood of adverse health effects in wildlife. Here, using Japanese quails (Coturnix japonica) as our model, we show that females preferred GBH-contaminated food compared to control food. In females, exposure to GBHs caused delayed plumage development, and GBH residues were present in eggs, muscles, and liver. These results indicate that female preference is not adaptive, potentially exposing nontarget animals to greater risk of adverse effects of GBHs in natural and agricultural environments. Our results on tissue residues suggest that further studies are needed to understand the risks of such residues in the food chain.

Phosphorus Taste Involves T1R2 and T1R3

Rodents consume solutions of phosphates and pyrophosphates in preference to water. Recently, we found that the preference for trisodium pyrophosphate (Na3HP2O7) was greater in T1R3 knockout (KO) mice than wild-type (WT) controls, suggesting that T1R3 is a pyrophosphate detector. We now show that this heightened Na3HP2O7 preference of T1R3 KO mice extends to disodium phosphate (Na2HPO4), disodium and tetrasodium pyrophosphate (Na2H2PO4 and Na4H2PO4), a tripolyphosphate (Na5P3O10), a non-sodium phosphate [(NH4)2HPO4], and a non-sodium pyrophosphate (K4P2O7) but not to non-P salts with large anions (sodium gluconate, acetate, or propionate). Licking rates for Na3HP2O7 are higher in T1R2 KO mice than WT controls; Na3HP2O7 preference scores are increased even more in T1R2 KO mice and T1R2+T1R3 double KO mice than in T1R3 KO mice; preference scores for Na3HP2O7 are normal in T1R1 KO mice. These results implicate each subunit of the T1R2+T1R3 dimer in the behavioral response to P-containing taste compounds.

Diet selection in pigs: choices made by growing pigs given foods of different protein concentrations

To test the proposition that growing pigs, when given a choice between two foods, are able to select a diet that meets their requirements, and to investigate the rules of diet selection, four foods (L, A, B and H) with similar energy yields, but different concentrations of crude protein (CP) (125, 174, 213 and 267 g CP per kg fresh food respectively) were formulated. The four foods were offeredad libitumeither singly, or as a two-way choice using all the six possible pairs, to 40 individually caged pigs from 12 to 30 kg live weight. On the single foods the rate of food intake fell from 1001 to 971 to 961 to 868 (s.e.d. 40) g/day (F < 0·05) as the protein concentration of the foods increased from L to H; the growth rate followed an opposite trend (492, 627, 743 and 693 (s.e.d. 31) g/day respectively;P< 0·01). When the pigs had to select between two foods limiting in protein (L and A) the less limiting one was preferred (710 (s.e. 200) g A per kg total food intake; the protein concentration of the selected diet was 160 (s.e. 10) g CP per kg). On the choice between B and H (a choice between a food with protein concentration close to requirements and a food with protein excess) the lower food was markedly preferred (928 (s.e. 4) g B per kg total food intake; the protein concentration of the selected diet was 218 (s.e. 1) g CP per kg). When the animals were given a choice between two foods, a combination of which was non-limiting (pairs LB, LH, AB and AH), the protein concentrations of the selected diets were not different between treatments (208, 204, 202 and 205 (s.e.d. 13) g CP per kg respectively) and they also declined systematically with time and weight. The growth rate of the animals on these pairs were 752, 768, 769 and 763 (s.e.d. 54) g/day (P > 0·05), which were not significantly different from the highest growth rate achieved on a single food. The results suggest that pigs, when given a choice between a suitable pair of foods, are able to choose a balanced diet and to change its composition to reflect their changing requirements. The choice-feeding method may well be useful as an effective and economic way of estimating and meeting requirements, and of measuring the growth potential of pigs.

Dietary Nitrogen Intake Regulates Hepatic Malic Enzyme Messenger Ribonucleic Acid Expression

Increased dietary protein intake rapidly (3 h) decreases malic enzyme and increases hepatic histidase mRNA expression. Experiments were conducted to determine the role that individual dispensable amino acids and nonprotein N sources might have in regulating the activity of these enzymes and to determine if the addition of a N supplement to a practical broiler diet during the entire rearing period would reduce abdominal fat accumulation in broilers. Broiler chicks were fed a basal diet containing 22% protein or this diet supplemented with 9.5% l-Glu, 5% Gly, 6% l-Ala, 5.08% ammonium bicarbonate, or 4.25% dibasic ammonium phosphate for 24 h. Each of the dietary supplements added 0.90% total N to the diet. Hepatic malic enzyme mRNA expression was significantly (P < 0.05) depressed in chicks fed any of the supplemented diets compared with chicks fed the basal diet. Histidase mRNA expression, however, was only significantly increased in the chicks fed the basal diet supplemented with Gly. Broilers fed practical corn-soybean meal starter and developer diets supplemented with 2.3, 4.7, or 9.5% Glu from 0 to 40 d of age had significantly smaller abdominal fat pads relative to BW than broilers fed the unsupplemented corn-soybean meal diets. Feeding the Glu supplements, however, reduced the overall BW gain of broilers by 100 to 150 g compared with broilers fed the unsupplemented diets. The results suggest that hepatic mRNA expression of malic enzyme may be regulated by total dietary N intake, whereas hepatic mRNA expression of histidase may be regulated by specific amino acids.

The ability of laying hens to regulate phosphorus intake when offered two feeds containing different levels of phosphorus

The ability of laying hens to adjust their intake of available P (AP) was investigated with a maize-soyabean diet fed to forty-eight individually caged birds in a 2 x 4 factorial experiment. From 19 to 25 weeks of age (phase 1) twenty-four birds were fed a normal-P (NP) diet (2.2 g AP/kg DM) and twenty-four were fed a low-P (LP) diet (1.1 g AP/kg). LP eggs were lighter (51 v. 54 (SEM 1.0) g; P<0.05), providing evidence that the LP diet was deficient in AP. From 25 to 28 weeks of age six hens from each phase 1 treatment were fed either the NP or LP diet alone or a choice of the LP and NP feeds or a choice of the LP feed and a phytase-supplemented (PP) feed (LP diet with 400 microbial phytase units/kg). With a choice of the NP and LP feeds, the hens fed the LP diet in phase 1 ate a smaller proportion of the LP feed (34 (SEM 12.0) %) than the hens fed the NP diet in phase 1 (72 (SEM 12.0) %; P<0.05), showing that P deficiency influenced subsequent selection for AP, i.e. an appetite for P was demonstrated. In those birds offered the LP and PP feeds, the presence of phytase in one of the two feeds significantly alleviated the effect of P deficiency on egg and body weights. The proportion of the LP diet chosen was not significantly affected by phase 1 treatment; it was not necessary for the hens to eat more than 50 % of PP feed.

Investigation on the possibility of reducing protein, phosphorus, and calcium requirements of laying hens by manipulation of time of access to these nutrients

Experiments (Exp.) were conducted to determine whether the daily requirement of laying hens for protein, P, and Ca can be reduced by providing the hens with adequate levels of these nutrients only during those hours of the day that the physiological need for these nutrients for formation of various components of eggs are increasing. In Exp. 1, birds of the positive control were fed a 16% protein diet and birds of the negative control were fed a 13% protein diet continuously during the light period (0500 to 2100 h). The other groups were fed the 16% protein diet during the morning (0500 to 1300 h) and the 13% protein diet during the afternoon (1300 to 2100 h) or vice versa. The design of Exp. 2 was similar to Exp. 1. The birds of the positive control were fed a 0.4% available P (AP) and the birds of the negative control were fed a 0.2% AP diet, with other groups receiving the high-low AP or the low-high AP diets during the morning and the afternoon, respectively. The birds of the negative controls in these Exp. had almost comparable performance to those fed the other dietary treatments. As a result, these Exp. did not have negative controls for comparison of different dietary treatments. Additionally, regardless of dietary treatments, birds consumed about 40% of their daily feed intake during the morning and about 60% during the afternoon in these Exp. Due to these two shortcomings, it was not possible to reach to a decisive conclusion pertaining to the objectives of the Exp. The results of Exp. 3 indicated that the above pattern of daily feed intake was not due to an increased appetite for Ca during the afternoon hours for shell formation. Various indices of shell quality were not improved when most parts of the daily Ca need was fed during the afternoon and evening and were not reduced when most parts of the daily Ca need was fed during the morning.

Further investigations on the effect of dietary manipulation of protein, phosphorus, and calcium for reducing their daily requirement for laying hens

Experiments were conducted to determine the possibility of reducing the daily requirement of laying hens for Ca, available P (AP), and protein by providing the hens with adequate levels of these nutrients only during those hours of the day that the physiological need for these nutrients for formation of various components of the eggs are increasing. The results of the Ca experiment indicated that the daily Ca requirement cannot be reduced by providing the hens with adequate levels of Ca during the afternoon (1500 to 2100 h) and inadequate Ca level during the morning (0500 to 1500 h). Providing the hens with most of the daily Ca need during the afternoon did not have a beneficial effect on shell quality as compared to the control group that received a diet with 3.5% Ca during the morning and the afternoon. On the other hand, inadequate Ca intake during the afternoon adversely affected shell quality as compared to the control group (P < 0.05). The AP experiment indicated that egg production performance and shell quality can be maintained satisfactorily as long as the daily intake of AP is adequate, regardless of whether most of the AP is consumed during the morning or the afternoon. Egg production and shell quality of hens fed a diet with 0.4% AP during the morning and 0.1% AP during the afternoon or 0.1% AP during the morning and 0.4% AP during the afternoon were not different than the control group that received a diet with 0.25% AP during the morning and the afternoon. The results of two protein experiments failed to indicate that egg production performance of laying hens can be maintained satisfactorily by providing them with an adequate level of protein (16%) only during the morning and inadequate level of protein (10%) during the afternoon or, conversely, compared to the control group that received a diet with 16% protein both during the morning and afternoon (P < 0.05). The supply of adequate protein with sufficient amino acids, during the morning and the afternoon, was required for satisfactory maintaining egg production performance. Under the conditions selected for the conduct of this study, the results of the current experiments, combined with those of a previous report, failed to support the hypothesis that satisfactory performance may be maintained by providing the hens with adequate levels of protein, AP, and Ca only during those hours of the day when the physiological need for these nutrients for formation of various components of the egg are increasing.

The effects of enzyme and inorganic phosphorus supplements in wheat- and rye-based diets on laying hen performance, energy, and phosphorus availability

A total of 640 22-wk-old pullets (Shaver SX 288) housed four birds per cage in 40 experimental units (four cages per unit), were randomly assigned eight experimental diets in a 2 x 2 x 2 factorial arrangement. The treatments consisting of two grain sources (wheat and rye) two levels each of crude enzyme preparation (0 and 0.1% Roxazyme G), and added inorganic phosphorus (0 and 0.105%) were fed for five 4-wk periods. At 42 wk of age, 40 individually caged layers were fed the experimental diets with 0.3% chromic oxide (5 individual birds per treatment) to determine AMEn and available P. Plasma P and Ca were also determined. Egg production, feed intake (FI), egg weight, feed efficiency (FE), and specific gravity of eggs were significantly (P < or = 0.05) affected by the experimental periods. Hens fed wheat-based diets had higher (P < or = 0.05) tibia ash (54.3 vs 52.5%), excreta dry matter (22.0 vs 17.7%), and eggshells with > or = 1.080 specific gravity (93.5 vs 89.9%) than birds fed rye. Enzyme supplementation significantly improved AMEn (P < or = 0.01) and FE by 6.2 and 3%, respectively. Egg production increased numerically from 87.6 to 90.1%. Inorganic P supplementation significantly increased egg production (P < or = 0.01), FI, FE, and AMEn (P < or = 0.05) by 4.4, 2, 3, and 2.8%, respectively, but significantly (P < or = 0.05) decreased the proportion of eggs having a specific gravity > or = 1.080 from 92.8 to 90.6%. The enzyme and inorganic P supplementation had no effect on tibia ash content and total plasma Ca and P. Rye can be used in layer rations yielding satisfactory performance when fed with a fungal crude enzyme preparation high in pentosanase/xylanase activity.

Effect of dietary sodium zeolite A and graded levels of calcium on growth, plasma, and tibia characteristics of chicks

Sodium zeolite A (SZA), a synthetic sodium aluminosilicate having high ion-exchange capacity, has been shown to increase eggshell specific gravity in laying hens and to improve Ca utilization in chickens. A 4 x 2 factorial arrangement of treatments was used to investigate the effect of dietary Ca (.6, .8, 1.0, and 1.2%) and SZA (0 and .75%) on growth, plasma, and tibia characteristics of chicks from 5 to 15 days of age. Increasing dietary Ca linearly increased (P less than .05) Ca and alkaline phosphatase (AP) in plasma and increased tibia shearing force and percentage ash, Ca, and P in tibiae. However, dietary Ca linearly decreased (P less than .05) inorganic P and Mg in plasma and Mg and Mn in tibiae. Sodium zeolite A decreased (P less than .05) plasma P and AP and tibia Mg but increased (P less than .05) tibia Ca, Zn, Al, and Mn concentrations. Tibia ash and shearing force were increased in chicks fed SZA receiving inadequate dietary Ca, but they were decreased in chicks fed SZA and excess Ca (Ca by SZA interaction, P less than .05). Tibia density showed a similar trend, but the effect was not significant (Ca by SZA interaction, P less than .12). The addition of SZA enhanced tibia ash, density, and shearing force when dietary Ca was low; however, when added to diets containing 1.2% Ca, SZA reduced many bone mineralization indices with the exception of tibia Ca.

Comparison of the effects of synthetic and natural zeolite on laying hen and broiler chicken performance

Three experiments were conducted to investigate the effect of zeolites on laying hens (Experiments 1 and 2) and broiler chickens (Experiment 3). Each experiment used corn and soybean meal-based practical diets. Experiment 1 was a 90-day trial and used 200 40-wk-old laying hens. The basal diet contained 2.75% calcium and .7% total phosphorus. The dietary treatments were the basal diet and the basal diet plus 1.5% synthetic zeolite (SZ; Ethacal). Experiment 2 was a 56-day trial and used 360 36-wk-old laying hens. The dietary treatments were .12, .22, .32, and .42% nonphytin phosphorus with and without 1.0% SZ and 1.0% natural zeolite (NZ; Zar-Min). All diets contained 3.5% calcium. Experiment 3 utilized 240 broiler cockerels from 1 to 16 days. The dietary treatments were two calcium levels (.65 and 1.0%) with and without 1.0% supplementary SZ and NZ. In Experiment 1, egg specific gravity was significantly increased with SZ supplementation. Egg weight and egg production were unaffected. Phytin phosphorus retention and plasma dialyzable phosphorus were significantly reduced by SZ. In Experiment 2, egg specific gravity was not affected by SZ or NZ. Egg weight, egg production, plasma dialyzable phosphorus, and the retention of phosphorus and phytin phosphorus were significantly reduced by SZ with the effect on egg weight and egg production being the most severe at the lower levels of dietary nonphytin phosphorus. Natural zeolite had no effect on egg weight, egg production, plasma calcium, plasma phosphorus, or on the retention of calcium, phosphorus, and phytin phosphorus. In Experiment 3, weight gain and percentage tibia bone ash were significantly reduced by SZ. The SZ had no effect on the incidence and severity of tibial dyschondroplasia. Weight gain, feed efficiency, and the incidence and severity of tibial dyschondroplasia were significantly reduced and the percentage bone ash significantly increased by 1.0% calcium. Natural zeolite significantly improved feed efficiency and had no effect on any other parameter measured.

Evaluation of the dietary interaction of calcium and phosphorus in the high producing laying hen

1. In a 6 x 7 factorial experiment using 2688 22-week-old laying hens of the Lohmann-SL strain kept in cages (4 birds/cage), diets containing six calcium (20, 25, 30, 35, 40, 45 g calcium/kg) and seven phosphorus concentrations (3.2, 4.2, 5.2, 6.2, 7.2, 8.2, 16.2 g total phosphorus/kg (Pt)) were combined orthogonally. The resulting 42 treatments were replicated 8 times so that a replicate consisted of a double cage of 2 x 4 hens. The experiment lasted 40 weeks (10 x 28 days). 2. The experimental diets, based on maize and soyabean meals contained 11.5 MJ metabolisable energy/kg and 175 g/kg protein. Different dietary calcium and phosphorus contents were obtained by substituting oat hulls with limestone and dicalcium phosphate. 3. Mortality, egg production, egg weight, egg mass, food intake and food conversion efficiency were determined as well as the breaking strength, thickness of shells and the percentage of eggs with defective shells. 4. All responses measured were significantly influenced by the variance sources (calcium, phosphorus, interaction). Most of the production traits responded asymptotically to increasing dietary phosphorus concentration, the greatest increases or decreases generally being seen between 3.2 and 5.2 g Pt/kg. Further but weaker increases were seen between 5.2 and 8.2 or 16.2 g Pt/kg. 5. Increases in dietary calcium content always resulted in curvilinear responses. In all cases optimal effects were obtained with diets containing 25 g calcium/kg and the worst values at 45 g calcium/kg. The interaction between calcium and phosphorus was recognised by strong performance depressions and a high mortality at combinations of the lowest phosphorus concentration (3.2 g/kg) with high calcium contents (35 to 45 g/kg). These were largely offset by increasing dietary phosphorus. Thus, between 7.2 and 16.2 g Pt/kg and 25 and 45 g Ca/kg a plateau was formed where only small differences in egg production were observed. 6. From the three egg shell characteristics measured, breaking strength and shell thickness responded differently to the percentage of eggs with defective shells. While breaking strength and shell thickness were respectively negatively and positively influenced by increasing dietary phosphorus and calcium contents, both elements affected the proportion of eggs with defective shells.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of dietary calcium, phosphorus, chloride, and zeolite on the development of tibial dyschondroplasia

The effect of synthetic zeolite was investigated on the development of tibial dyschondroplasia in young broilers fed diets in which the dietary levels of calcium, phosphorus, and chloride ranged from adequate to deficient. In the first two experiments the calcium level was maintained at .65% and four combinations were fed of .30% and .15% chloride and .75% and .50% phosphorus with and without 1% zeolite. Feeding the high phosphorus diet caused a high incidence of tibial dyschondroplasia that was lowered by feeding 1% zeolite. In both experiments the feeding of zeolite at a low level of dietary phosphorus caused a significant lowering of 16-day weight and bone ash. In the third experiment, when diets containing all combinations of .65% and .80% calcium and .50% and .60% phosphorus were fed, the addition of 1% zeolite caused a significant lowering of the 16-day weight, bone ash, and incidence, score, and percentage severe tibial dyschondroplasia. Once again as in the previous two experiments, there was a significant interaction between dietary phosphorus level and zeolite and 16-day weight and bone ash. Feeding zeolite significantly decreased phytate phosphorus retention.

Effects of different short-term dietary phosphorus levels on egg specific gravity and blood phosphorus of hens

In the first 2 experiments, laying hens were fed a diet containing .30% phosphorus for a preliminary period of 3 days. At the beginning of the experimental period, hens were fed .30, .75, or 1.40% phosphorus with 3.50% calcium. Another group of hens was fed .75% phosphorus and 1.40% calcium. Specific gravity of the eggs and blood serum inorganic phosphorus were determined and compared with those from control hens continuously fed a diet containing .75% phosphorus and 3.50% calcium. Both high phosphorus and/or low calcium decreased the specific gravity of eggs and increased the serum phosphorus level. In experiment 2, hens were fed different levels of phosphorus at different times of the day. Birds receiving 1.40% phosphorus between 0700 and 0930 hr and .30% phosphorus between 0930 and 2000 hr (Treatment 2) laid eggs with higher specific gravity than hens fed .30% phosphorus between 0700 and 0930 hr and 1.40% phosphorus between 0930 and 2000 hr (Treatment 3). there was no further improvement in egg shell quality over that from hens fed .75% phosphorus for both time periods (0700 to 2000 hr). In both experiments it was apparent that the dietary phosphorus level affected egg shell quality.