Effect of restricted feeding on hen performance,egg quality and organ characteristics of individual laying hens

This study was to assess the impact of permanent or temporary restricted feeding on laying hen production traits,physiology,and egg quality.Two hundred and forty individually housed ISA Brown hens were monitored across 2 phases,assigned to 3 treatments:ad libitum feeding(ALF),temporary restricted feeding(TRF)and permanent restricted feeding(PRF),n=80 hens per treatment.In Phase 1(P1),22 to40 weeks,the TRF and PRF hens were offered 115 g of feed daily.In Phase 2(P2),41 to 46 weeks,the TRF hens were transitioned to ALF status while the ALF and PRF hens remained as in P1.From 35 to 40 weeks,eggs were collected once weekly from 15 hens per treatment and assessed for differences in albumen,yolk,and shell variables.At 45 weeks,10 hens each from the ALF and PRF groups were euthanized and differences in organ characteristics were assessed.In P1,feed intake,feed to egg conversion ratio and body weight(BW)change were lower(P<0.01),while albumen height and Haugh unit were higher(P<0.01)in both PRF and TRF hen treatments compared to hens allocated the ALF treatment.In P2,TRF and ALF hens had a higher egg production and egg mass than PRF(P<0.01)than ALF.Body weight change in P2 was higher in TRF and similar in both ALF and PRF,while feed intake and feed conversion ratio were higher in TRF followed by ALF and least in the PRF treatment group(P<0.01).At 45 weeks ALF hens had a greater abdominal fat pad weight and fatty liver haemorrhagic syndrome lesion score compared to PRF.Restricting hens to 115 g of feed per day from point of lay restrained BW,improved feed conversion ratio and albumen quality and reduced abdominal fat pad deposition and clinical signs of fatty liver haemorrhagic syndrome in individually housed laying hens.

Effect of Complete Feed Feeding Level and Morning Glory on Growing Pig Performance

A total of 60 castrated male pigs (Yorkshire x Duroc, initially 17.36 kg) were used in a 42-day trial to evaluate the effect of complete feed feeding level and morning glory on growth performance of growing pigs. Pigs were allotted to pens and randomly assigned to three dietary treatments: A) completed feed fed ad libitum;B) complete feed fed at 75% of intake of treatment A, and C) treatment B with ad libitum availability of morning glory. The design was a completely randomized design (CRD) with five pens (replications) of each treatment with four pigs per pen. Average daily feed intake (dry matter basis) was higher (P < 0.001) for pigs fed treatment A (1420 g/d) compared to treatment B (1048 g/d) as expected, with treatment C intermediate (1178 g/d;1048 g/d complete feed + 130 g/d morning glory). Average daily weight gain of pigs fed ad libitum was greater (P < 0.001) than pigs restricted fed with pigs which provide morning glory intermediate (871, 674 and 714 g, respectively). Feed efficiency improved (P < 0.024) for pigs fed the restricted feed level compared to pigs fed complete feed ad libitum or pigs restricted fed but provided morning glory (1.63, 1.56 and 1.65, respectively). For economics, feeding complete feed ad libitum improved (P < 0.001) income over feed cost compared to restricted feeding or providing morning glory (USD 41.48, 33.42, and 33.89/pig, respectively). In conclusion, feeding growing pigs a complete diet ad libitum resulted in the greatest growth rate and profitability. Offering morning glory (Ipomoea. aquatica) to pigs fed a restricted level of complete feed did improve final body weight, but the extra cost of feeding morning glory offset this advantage resulting in similar profitability on an income over feed cost basis.

Cortisol levels in skimmed milk during the first 22 weeks of lactation and response to short-term metabolic stress and lameness in dairy cows

Background： Cortisol is secreted into blood in reaction to acute stress, but also in phases of diminished feed intake and changed animal behavior. As cows do not always show clear signs of discomfort, reliable diagnostic markers could be used to provide information regarding individual cows＇ distress. The objective of this study was to establish an ether free immunoassay for the detection of cortisol and to determine values during the first 22 weeks of lactation. Furthermore, the response in milk cortisol levels was assessed during times of metabolic stress and pain associated symptoms of lameness. Methods： Milk yield and composition, blood serum glucose, NEFA and BHBA as well as milk cortisol were determined in 24 multiparous Holstein-Friesian cows over the course of the first 22 weeks of lactation. Animals were further checked for signs of clinical diseases on a daily basis. Two feed restrictions over three days （FR; 70 % of precious ad libitum intake） were performed during the 4th wk and the 21st wk, respectively. An ELISA for cortisol measurement in easily accessible bovine skimmed milk was established and applied. Results： On the last day of FR in early lactation, a reduction in milk yield and changes in serum metabolites compared to respective previous values were detected. The FR in mid-lactation resulted in no changes in milk production and serum metabolites. Milk cortisol was highest during first wk of lactation and remained on comparable levels thereafter. Milk yield and composition were not influenced by FR. Lameness resulted in enhanced milk cortisol levels. Conclusion： Milk cortisol could be used as an indicator of painful symptoms such as lameness. Higher values of milk cortisol levels during first wk of lactation should be taken into account for interpretation.

Early-age feed restriction affects viability and gene expression of satellite cells isolated from the gastrocnemius muscle of broiler chicks

Background： Muscle growth depends on the fusion of proliferate satellite cells to existing myofibers. We reported previously that 0-14 day intermittent feeding led to persistent retardation in myofiber hypertrophy. However, how satellite cells respond to such nutritional insult has not been adequately elucidated. Results： One-day-old broiler chicks were allocated to control （Con, ad libitum feeding）, intermittent feeding （IF, feed provided on alternate days） and re-feeding （RF, 2 days ad libitum feeding after 12 days of intermittent feeding） groups. Chickens were killed on Day 15 and satellite cells were isolated. When cultured, satellite cells from the IF group demonstrated significant retardation in proliferation and differentiation potential, while RF partly restored the proliferation rate and differentiation potential of the satellite cells. Significant up-regulation of insulin like growth factor I receptor （IGF-IR） （P〈O.05） and thyroid hormone receptor o （TRo） （P〈O.05）, and down-regulation of growth hormone receptor （GHR） （P〈O.01） and IGF-I （P〈O.01） mRNA expression was observed in freshly isolated IF satellite cells when compared with Con cells. In RF cells, the mRNA expression of IGF-I was higher （P〈O.05） and of TRa was lower （P〈O.01） than in IF cells, suggesting that RF restored the mRNA expression of TRa and IGF-I, but not of GHR and IGF-IR. The Bax/Bcl-2 ratio tended to increase in the IF group, which was reversed in the RF group （P〈O.05）, indicating that RF reduced the pro-apoptotic influence of iF. Moreover, no significant effect of T3 was detected on cell survival in IF cells compared with Con （P〈O.O01） or RF （P〈O.05） cells. Conclusions： These data suggest that early-age feed restriction inhibits the proliferation and differentiation of satellite cells, induces changes in mRNA expression of the GH/IGF-I and thyroid hormone receptors in satellite cells, as well as blunted sensitivity of satellite cells to T3, and that RF partially reverses these effects. Thus, a moderate nutritional strategy for feed restriction should be chosen in early chick rearing systems.

Influence of Early Quantitative Feed Restriction on Performance and Carcass Characteristics of Broiler Chickens

An experiment was conducted to study the influence of eady quantitative feed restriction on the performance and carcass characteristics of broiler chickens. Two hundred 8-day-old commercial Avian male broiler chicks were assigned to four groups randomly, with 50 broilers each. At the age of 8 days the broilers were restricted to 90%, 80% or 70% of the ad libitum intake for 7 days. When the restricion was finished, all birds received feed ad libitum again. The results showed that diet restriction resulted in a reduction in body weight and daily gain during the restriction period （P 〈0.05）. The birds restricted to 90% of the ad libitum intake showed the occurring of growth compensation in the 3rd week. The birds restricted to 80% and 70% of the ad libitum intake had growth compensation in the 4th week. No significant differences between the effects of the restriction and the control on final body weight, growth rate, feed conversion efficiency and carcass characteristics （P 〈0.05）.

Economic Analysis of the Use of Restrictive Food Management in the Cultivation of Tilapia(Oreochromis niloticus)in a Recirculation System

The development of more adequate food programs regarding the intensity and duration of the restriction can be an effective way to minimize the effects of exaggerated food consumption and its negative consequences for the economy of the business.In this sense,juvenile Nile tilapia(Oreochromis niloticus)(137±3 g)were submitted to different feeding strategies in a recirculation system.Five feeding strategies were tested in subsequent weekly cycles:continuous feeding;skipping one meal a week;suppression of two non-consecutive meals a week;suppression of three non-consecutive meals a week;suppression of four non-consecutive meals a week.Productive performance,feed consumption in the post-restriction period and economic indicators were evaluated through projections and profitability analyses.Compensatory intake occurred in all tested groups,so that the total feed intake(FI)did not differ significantly between them(p>0.05).Moderate food restriction provided a linear increase in the relative gross margin for each treatment with each change in salary level,as well as greater profitability when compared to the respective control group(p<0.05).

The Effect of Quantitative Feed Restriction Duration on Growth Performance and Carcass Characteristics of Broiler Chickens

The growth productivity of broilers is influenced by improving growth performance through improving body weight, average daily gain, and feed conversion rate. The objective of the study was to determine the effect of quantitative feed restriction duration on growth performance and carcass characteristics of broilers. A total of 144 day-old broiler chicks were reared in a deep litter system until slaughter at 42 days. Chicks were randomly allocated to three treatments which were replicated three times with 16 birds per replicate. The three treatments were the control (T1), one week of feed restriction (T2), and two weeks of feed restriction (T3). Birds were fed with starter, grower and finisher diets. The average daily gain (ADG), average daily feed intake (ADFI), and the feed conversion ratio (FCR) were computed for each week. Carcass weight and internal organs weights were measured. The body weight gained by the birds in T1 was similar to the birds that were restricted for a week. The treatments had a significant effect on the average daily gain in weeks 4, 5, and 6. The ADG for T2 was higher (P < 0.05) at week 5 after 1 week of restriction, than T1 and T3. The feed conversion ratio was significantly higher in T3 after 2 weeks of restriction. In T2 and T3, feed intake was significantly lower than in birds fed ad libitum at week 4 at the start of the treatment. There was no significant effect on the relative weights of heart weights, liver, gizzard, feet, and heads among the treatment groups except for intestine weight which was lower (P < 0.05) in T1 than T2 and T3. It was concluded that broilers that were restricted for one week had a positive result in growth performance. Feed restriction had minimal effect on the organ weights of broiler chickens.

Examination of the molecular control of ruminal epithelial function in response to dietary restriction and subsequent compensatory growth in cattle

Background： The objective of this study was to investigate the effect of dietary restriction and subsequent compensatory growth on the relative expression of genes involved in volatile fatty acid transport, metabolism and cell proliferation in ruminal epithelial tissue of beef cattle. Sixty Holstein Friesian bulls（mean liveweight 370 ± 35 kg;mean age 479 ± 15 d） were assigned to one of two groups：（i） restricted feed allowance（RES; n = 30） for 125 d（Period 1） followed by ad libitum access to feed for 55 d（Period 2） or（ii） ad libitum access to feed throughout（ADLIB; n = 30）. Target growth rate for RES was 0.6 kg/d during Period 1. At the end of each dietary period, 15 animals from each treatment group were slaughtered and ruminal epithelial tissue and liquid digesta harvested from the ventral sac of the rumen. Real-time q PCR was used to quantify m RNA transcripts of 26 genes associated with ruminal epithelial function. Volatile fatty acid analysis of rumen fluid from individual animals was conducted using gas chromatography.Results： Diet × period interactions were evident for genes involved in ketogenesis（BDH2, P = 0.017）, pyruvate metabolism（LDHa, P = 0.048; PDHA1, P = 0.015） and cellular transport and structure（DSG1, P = 0.019; CACT, P = 0.027）. Ruminal concentrations of propionic acid（P = 0.018） and n-valeric acid（P = 0.029） were lower in RES animals, compared with ADLIB, throughout the experiment. There was also a strong tendency（P = 0.064）toward a diet × period interaction for n-butyric with higher concentrations in RES animals, compared with ADLIB, during Period 1.Conclusions： These data suggest that following nutrient restriction, the structural integrity of the rumen wall is compromised and there is upregulation of genes involved in the production of ketone bodies and breakdown of pyruvate for cellular energy. These results provide an insight into the potential molecular mechanisms regulating ruminal epithelial absorptive metabolism and growth following nutrient restriction and subsequent compensatory growth.

Effects of wet feeding and early feed restriction on blood parameters and growth performance of broiler chickens

The aim of the study was to investigate the effects of early feed restriction(FR) with wet feeding on size of small intestine, blood lipids and performance parameters in broilers from d 1 to 42. A total of 160 oneday-old male broiler chickens were randomly allocated to 4 treatments with 4 pens per treatment and 10 chickens per pen, in a fully randomized 2×2 factorial arrangement, two feeding arrangement; providing feed ad libitum(Full Fed) or FR by 50% between days 6 to 12, and feed in either wet or dry form(wet form, 1.2 g water per 1 g dry feed). Body weight and feed intake of broiler chickens were determined at d 0, 21, and 42, and feed conversion ratio(FCR) was calculated. At d 42, two birds per replicate were euthanised for determination of carcass weight, organ weight and length, and also for blood parameters,which included high density lipoprotein(HDL), low density lipoprotein(LDL), total cholesterol and triglycerides(TG). The broilers fed wet form irrespective of FR throughout had superior body weight gain and carcass weight compared with birds fed dry diets at d 22 and 42(P < 0.05). The wet form with FR significantly showed lower FCR compared with the wet form and ad libitum at d 1 to 21(P < 0.05). The broilers fed wet form had significantly increased HDL, LDL, and total cholesterol and decreased TG(P < 0.05). In conclusion, wet form can improve performance growth and blood parameters, and the FR birds were able to attain normal market body weight at d 42, which suggests that growth compensation occurred.

A comparative study to determine the effects of breed and feed restriction on glucose metabolism of chickens

The glucose metabolism of poultry draws wide attention as they have nearly twice the fasting blood glucose than that of mammals.To define the relationship between glucose metabolism and breed of chicken,the outcomes from different growth rate chickens showed that Arbor Acres(AA)broilers,a well-known fast-growing breed,had a lower fasting blood glucose concentration and glucose clearance rate when compared to Silky chickens,a Chinese traditional medicinal chicken with black skin and a slow growth rate.Moreover,AA broilers had a relatively slow rise in blood glucose in response to oral glucose solution than the Silky chickens on 21 and 42 d(P<0.05),which is probably attributed to downregulated expression of pancreatic insulin(INS),and upregulated transcription of phosphoenolpyruvate carboxy kinase 1(PCK1)and glucose transporter 2(GLUT2)in the liver of AA broilers(P<0.05).In response to feeding restriction from 7 to 21 d,both the fasting blood glucose and the response speed of AA broilers to oral glucose were increased on d 21(P<0.05),and the serum glucose concentrations after 3 weeks compensatory growth were improved by early feed restriction in AA broilers.Feed restriction could also upregulate the mRNA level of pancreatic INS on d 21 and 42,as well as decrease the expressions of PCK1,glucose-6-phosphatase catalytic(G6PC),and GLUT2 in the liver on d 21(P<0.05)when compared to the free feeding group.These results revealed that Silky chickens have a stronger capability to regulate glucose homeostasis than AA broilers,and feed restriction could improve the fasting blood glucose and the response to oral glucose of AA broilers.