South African Journal of Animal Science

Laying hens behave as omnivores with poultry meal included in their diet

This study was conducted to determine egg yield performance and quality, animal partiality to poultry meal, and consumer preferences for eggs produced by various feeding methods. A total of 72 Nick Brown laying hens, aged 22 weeks, were offered three feeding methods with 24 replicates per treatment and one hen per experimental unit. These methods consisted of i) vegetarian (no poultry meal), ii) omnivorous (5% poultry meal), and iii) a choice between vegetarian and omnivorous. Feed and water were provided ad libitum. The study lasted for 10 weeks. Feeding methods did not affect feed intake, feed conversion ratio, egg yield, and egg quality. However, they affected the malondialdehyde (MDA) value of eggs on the 42nd day of storage significantly (P <0.05). The highest MDA value was obtained from the eggs of 'omnivorous' hens. More hens (51.4%) in the choice group preferred omnivorous feed to 'vegetarian'. Panellists found organoleptic differences among sample eggs from hens subjected to various feeding methods. They reported that the eggs obtained from vegetarian hens were preferable. The conclusions were that i) no feeding method changed egg yield performance and quality, ii) omnivorous feeding shortened the shelf-life of eggs, iii) hens with a choice of feed did not reject the omnivorous diet, but increased their intake, and iv) the panellists disliked eggs from the omnivorous hens. Finally, these preferences should be considered in legislation for poultry feeding and animal husbandry.

Pelleting increases the metabolizable energy of de-hulled sunflower seed meal for broilers

The study examined the effects of two methods of processing de-hulled sunflower seed meal (SFM) from the same batch of sunflower seeds. Sunflower seed meal was fed to broilers as meal (MSFM) or after it had been pelleted (PSFM) at 75 °C and 360 kPa pressure to pass through a 3 mm mesh. Three diets were prepared, namely a balancer feed (BF) and two diets containing 200 g/kg MSFM or 200 g/kg PSFM. They were fed to 30 pens (two birds each) with male Ross 308 broilers, from 8 to 21 days old, following randomization. Data were analysed by ANOVA. Two pre-planned orthogonal contrast tests were performed to compare overall differences between the diets containing SFM and BF and between diets containing the MSFM and PSFM. The BF had a very different nutrient composition from the complete feeds containing SFM so, as expected, there were differences in growth performance and nutrient retention. The diet containing PSFM had greater apparent metabolizable energy corrected for N retention (AMEn) and dry matter retention (DMR) than that containing MSFM. The use of the substitution method showed the PSFM had AMEn that was 18% greater than the MSFM (8.79 vs 7.47 MJ/kg DM). Under the conditions of the current study, incorporating PSFM in a mash broiler feed increased dietary AMEn compared with the same feed containing MSFM. Further studies are needed to identify whether the benefits of pre-pelleting SFM remain after this product has been incorporated in complete pelleted broiler feeds.

A review of artisanal cheese making: An African perspective

Artisanal cheeses and other fermented milk products have long been part of the diet of African rural communities. Cheese is a source of nutrients that are essential to the development and growth of children in rural areas, where intake of amino acids, vitamin A, vitamin B12, calcium, phosphate, and polyunsaturated fatty acids may be limited. Wara, Karish, Ayib, Takammart, Wagashi, Domiati, and Ras are prominent cheeses of African origin. Artisanal cheese making should be expanded to improve people's nutritional status at low cost, stimulate the local economy, and empower small-scale farmers. This review firstly gives an overview of artisanal cheese production and consumption, and evaluates opportunities and challenges, while focusing on an African perspective. Secondly, it provides an insight into strategies that could improve cheese making at small-scale level. Possible areas of research and knowledge gaps are highlighted, particularly ways of improving cheese quality and safety.

Modelling lactation curves for fat-to-protein ratio of milk in the first three lactations of Polish Holstein-Friesian cows

Among milk traits, fat-to-protein ratio (FPR) is considered a potential measure of a cow's energy status and is one of the selection criteria necessary to improve metabolic stability. Further genetic analyses require an appropriate model that describes the pattern of FPR changes throughout lactation. The objective of the study was to examine five mathematical functions to describe the lactation curve for FPR in the first three lactations of Polish Holstein-Friesians. The dataset contained FPR records for 5690 cows in the first lactation, 4081 cows in the second, and 2636 cows in the third lactation based on 48908, 34706, and 22097 test-day (TD) records, respectively. Using the MIXED procedure of SAS statistical analytics software, ten linear models (five with fixed effects only, and five with the additional random effect of cow) were fitted to the TD records. The goodness of fit was tested with Akaike's information criterion, residual variances and the correlation coefficient between the actual and estimated values. The model proposed by Ali and Schaeffer (1987) had the best fit to FPR in the first three parities, and the model of Wilmink (1987) provided the worst fit. The correlation coefficient between the actual and the estimated values of FPR was higher for models that included the random cow effect compared with models without this effect.

Effects of feeding system and pre-partum supplementation on the ß-carotene status of South African Holstein cows

The objectives were to investigate the ß-carotene status of dairy cows under various production systems, and to determine the effect of pre-partum ß-carotene supplementation on their post-partum ß-carotene status. Ten farms were selected from each of the three production systems, namely pasture-based, hay-based total mixed ration (TMR) and silage-based TMR. Twenty cows per farm were sampled in each system, and blood plasma ß-carotene concentration was determined with a portable spectrophotometer (n = 200 cows per system). Mean blood ß-carotene concentrations of pasture-fed cows were 5.54 mg/L, and were higher (P <0.05) than concentrations of cows on hay-based (2.98 mg/L) and maize silage-based TMR systems (1.71 mg/L); in ß-carotene status, therefore, these systems were optimal, marginal, and deficient, respectively. In the second experiment, 10 cows received a hay-based control TMR, and 10 were supplemented with 1.2 g/day of ß-carotene pre-partum from day -56 to calving and monitored until day 56 postpartum. The supplemented cows were in optimal ß-carotene status until calving, with a minor carry-over effect until 10 days post partum, and then declined gradually in status until they needed supplementation. The ß-carotene status between the groups differed from three weeks pre-partum to two weeks post partum, with the control group being marginal to deficient from three weeks pre-partum onwards. Forage type and its ß-carotene content play a major role in the ß-carotene status of cows and more research is needed on the potential storage and mobilization of ß-carotene in cows.

Genetic effects on growth and egg production traits in two-way crosses of Egyptian and commercial layer chickens

A crossbreeding experiment was conducted between the Sinai (SI), an indigenous Egyptian strain, and the exotic Lohmann Brown (LB) breeds of chickens. A total of 790 chicks were produced in four genetic groups, namely SI x SI, LB x LB, SI x LB, and LB x SI. The objective was to estimate the direct additive effect (g i), individual heterosis (h i), and maternal additive effect (g m) for growth and reproduction traits. Direct additive effects were positive (P <0.01) for bodyweight (BW) at 4, 8, and 12 weeks old in favour of SI. For egg production traits, g i was positive for age at sexual maturity (ASM) and age at which the first 10 eggs were produced (P10), but negative for mean 10 egg production (MP10), egg number at 90 days (EN90),mean egg number at 90 days (MEN90), and egg mass (EM). The estimates of heterosis (%) were high for BW and daily gain except for BW0. Maternal effect estimates of BW and daily weight gain were significant (P <0.05) only for bodyweight at hatching (BW0), bodyweight at 4 weeks old (BW4) and daily weight gain from four to eight weeks old (DWG4-8). Thus, the Sinai and Lohmann Brown crossbreed produced favourable heterosis on the growth of the chicks. As an adapted indigenous strain, SI should be regarded as a dam line in crossing with LB, which has greater genetic potential for growth. Use of LB as a sire strain in conjunction with Sinai would increase egg production from the resulting hybrid chickens.

Relationship between plasma Cortisol level and bodyweight and antler size in farmed fallow deer

The aim of this study was to demonstrate the relationship between the plasma cortisol level and bodyweight and antler size in farmed male fallow deer (Dama dama) of various ages. The study involved 33 animals divided into three age groups: one year old, three years old, and older. Their bodyweight was measured and blood samples were taken twice a year during antler growth (May) and before the rut (September). Whole antlers were collected in September to measure their length and weight. The plasma cortisol concentration was determined with an immunoenzymatic method. The correlations between cortisol level and bodyweight were significant and positive in both May and September (P <0.05). There was a negative correlation between weight gain and change in cortisol levels (P <0.05). Thus, fallow deer with large seasonal changes in cortisol gained less weight from May to September. The results of the present study indicated that calmer animals with lower cortisol fluctuations should be selected for breeding, which would contribute to greater stability of weight gain.

Dietary nano-dicalcium phosphate improves immune response and intestinal morphology of broiler chickens

Various levels of substitution of nano-dicalcium phosphate (nCaHPO4) for the calcium and phosphorus supplied by limestone and monocalcium phosphate were evaluated, based on weight change, serum constituents, immune response and intestinal morphology of broiler chickens. The birds were assigned to five dietary treatments containing 0% (control), 40%, 60%, 80%, and 100% substitution levels of nCaHPO4 from days 0 to 42. Data were collected for blood measurement and intestinal morphology and analysed with one-way analysis of variance. Feeds substituted with 40% nCaHPO4 showed a higher mean value of final weight and better feed conversion. The results revealed similar haematological parameters across the treatment groups. At the same time, nCaHPO4 influenced most of the serum biochemical constituents, such as calcium, phosphorus, glucose, albumin, and total protein. High concentrations of total protein were observed for birds fed 60% nCaHPO4 compared with other treatments. The highest comparable means for albumin were observed in birds fed 40% and 60% nCaHPO4. Cholesterol levels were increased when birds were fed 0% and 40% of diets. Elevated serum phosphorus concentration was observed when 0%, 40%, 60% and 100% substitution levels were fed, whereas 80% presented the least mean value. The results also showed that birds fed 40% nano-dicalcium phosphate had the highest villi length, which signified improved absorption of minerals. In conclusion, 40% and 60% levels of nCaHPO4 could be used to boost immune response and functional intestinal morphology of broiler chicken with no negative effect on haematological parameters.

Essential oil and apple pomace affect fermentation and aerobic stability of alfalfa silage

This study assessed the effects of the additions of an essential oil (EO), composed of ricinoleic acid, cardol, cardanol, and apple pomace, on fermentation quality and aerobic stability of alfalfa silages. The experimental treatments consisted of T1) alfalfa (control), T2) alfalfa with EO, T3) alfalfa (75%) with apple pomace (25%), T4) alfalfa (75%) with apple pomace (25%) and EO, T5) alfalfa (50%) with apple pomace (50%), T6) alfalfa (50%) with apple pomace (50%) and EO, T7) alfalfa (25%) with apple pomace (75%), and T8) alfalfa (25%) with apple pomace (75%) and EO. The addition of apple pomace decreased the silage pH compared with the control (P <0.01). Apple pomace at 25% level increased the total volatile fatty acid (iVFA) content (P <0.05). Essential oil (EO) decreased tVFA and increased dry matter (DM) content 90 days after ensiling (P <0.01). Apple pomace decreased ammonia (N-NH3), crude protein (CP), and crude ash (CA) content and increased the amounts of neutral detergent fibre (NDF) and acid detergent fibre (ADF) (P <0.01). Essential oil and apple pomace (level 75%) increased effective digestibility (P <0.05). Apple pomace decreased aerobic stability and the addition of EO increased aerobic stability (P <0.05). Thus, use of apple pomace as a source of fermentable carbohydrate and/or the addition of EO in the preparation of high-quality alfalfa silage is recommended to offset its high buffering capacity and low carbohydrate content.

Addition of cellulolytic bacteria in complete feed block based on agro-industrial byproducts for Kacang goats

The research aimed at assessing the effects on nutrient digestion and ruminal fermentation by goats of a complete feed block (CFB) that incorporated agro-industrial by-products that were high in fibre and cellulolytic bacteria. Three Kacang goats, a native Indonesian breed, were used in a 3 x 3 Latin square experimental design with i) CFB without microbes (control), ii) CFB containing 1% Pseudomonas aeruginosa and 1% Acinetobacter baumannii, and iii) CFB containing 2% P. aeruginosa and 2% A. baumannii. Microbes in the CFBs consisted of lactic acid bacteria, yeast and cellulolytic bacteria that ranged from 10(6) to 10(8) cfu/g. The goats were fed each day at 08h00 and 16h00. The inclusion of P. aeruginosa and A. baumannii at 2% level reduced both neutral detergent fibre (NDF) and acid detergent fibre compared with other treatments. Goats fed on CFB with microbes had higher (P <0.01) digestibility of organic matter (OM) and NDF compared with control. The addition of P. aeruginosa and A. baumannii at 2% level increased (P <0.05) ruminal ammonia nitrogen (N-NH3), acetate, and total VFA. However, goats fed on CFB with microbes had lower (P <0.05) urinary N excretion, which improved (P <0.05) N retention compared with the control. It was concluded that a combination of lactic acid bacteria, yeast and cellulolytic bacteria in the CFB could modify fermentation in the rumen and increase the use of nitrogen in goats.

Effects of gender and dietary date palm extract on performance, carcass traits, and antioxidant status of Japanese quail

This research examined effects of gender and dietary inclusion of date palm extract (DPE) on growth, carcass characteristics, oxidative status and serum characteristics of Japanese quail. One thousand chicks were allocated to five replicates of treatment and gender groups composed of 20 chicks. The treatments were a basal diet and four groups augmented with 0.25%, 0.50%, 0.75%, and 1.00% DPE. The interaction of gender and treatment was significant for bodyweight (BW) at 42 days, average daily bodyweight gain (BWG), feed intake (FI), weights of most carcass components, and the serum profile. Females had better performance to 42 days than males (P <0.05). In addition, females had higher hot and cold carcass weights, breast percentage, liver percentage, intestine percentage, total protein, albumin, triglyceride (TRIG), total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress indexes (OSIs) (P <0.001). Males had higher percentages of hot carcass, cold carcass and heart, and their levels of cholesterol (CHOL), high-density lipoprotein (HDL), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) values were greater than females (P <0.001). Birds fed 0.50% DPE grew faster, were more efficient, and had heavier live and carcass weights at 42 days than those fed the basal diet. However, treatment effects and their interaction with gender on growth, feed intake and the serum profile were unremarkable compared to the gender main effect. Dietary augmentation with 0.50% DPE might enhance the performance of quail between 14 and 42 days old.