Effect of liquid-fermented potato hash, with or without exogenous enzymes, on carcass characteristics of growing pigs

 

 

P. Sebothoma^I; V.A. Hlatini^I; C.N. Ncobela^II; R.S. Thomas^{I, #}; M. Chimonyo^{III, *}

^IAgricultural Research Council-Animal Production (Nutrition Building), Private Bag X2, Irene, 0062, South Africa
^IIDepartment of Agriculture, Faculty of Natural Sciences, Mangosuthu University of Technology, P.O. Box 12363, Jacobs 4026, South Africa
^IIIFaculty of Science, Engineering and Agriculture, University of Venda, Private Bag X5050, Thohoyandou, 0950 South Africa

 

 

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ABSTRACT

The objective of the current study was to determine the effect of the dietary inclusion of liquid-fermented potato hash with or without exogenous enzyme on fermentation characteristics and carcass characteristics of pigs. Forty-two crossbred, male pigs (Large White × Landrace) aged 55 d with an average body weight of 25.5 ± 3 kg (mean ± standard deviation) were selected. Six pigs were randomly allocated to seven experimental dietary treatments. The dietary treatments included dry standard feed; liquid-fermented standard feed; liquid-fermented potato hash, 200 g/kg (as fed), with and without exogenous enzymes; and liquid-fermented potato hash, 400 g/kg (as fed), with and without exogenous enzymes. The back-slopping fermentation approach was followed to prepare experimental diets. Diets were formulated to provide 14 MJ/kg digestible energy (DE), 180 g crude protein (CP)/kg and 11.6 g lysine /kg. Lactic acid bacteria (LAB), Enterobacteriaceae, yeast, moulds, and Escherichia coli in the liquid-fermented diet with or without potato hash were influenced by the addition of enzymes. An effect of diet and enzymes was observed on lactic acid and water-soluble carbohydrates. The low and high liquid-fermented potato hash diets without enzymes had a higher pH than the low and high liquid-fermented potato hash diets with enzymes after 8 and 24 hr. Fermented potato hash with or without enzymes led to high drip loss and lean percentage. Carcass traits improved in pigs fed less liquid-fermented potato hash with or without enzymes.

Keywords: backfat thickness, bulkiness, feed processing, lactic acid, potato by-products

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Introduction

Waste from the food-processing industry can be used as food, feed, and fodder (Khedkar & Signh, 2018). Food waste can be partially incorporated into animal feed to reduce food wastage without compromising animal health and growth (Ncobela et al., 2017). A major challenge for the pig industry is the limited availability of energy sources, such as yellow maize, due to competition and harsh climatic conditions. Consequently, the use of by-products from the food processing industry as energy sources for pigs is gaining substantial momentum because is both economical and eco-friendly, since it can reduce waste disposal costs and pollution. By-products from the food processing industry are high in moisture and difficult to use without processing (Khedkar & Singh, 2018). They therefore decay readily, leading to nutrient losses and contamination with microorganisms and toxins in the process.

Potato hash, a mixture of potato skins, fats, and yellow maize obtained after the production of snacks, is an agro-industrial by-products that is available in appreciable quantities in South Africa (Ncobela et al., 2017). Nkosi & Meeske (2010) reported that potato hash contains 150 g DM/kg, 700 g starch/kg DM, 11.16 MJ ME/kg DM, 105 g CP/kg DM, 369.6 g NDF/kg DM, and 162.5 g ADF/kg DM. Incremental levels of unfermented potato hash increase rates of digesta passage, reduce nutrient digestibility, and compromise growth performance in pigs (Ncobela et al., 2021). For this reason, fermentation is required to break down the fibre matrix while prolonging shelf life. Liquid fermentation and the use of exogenous enzymes can disrupt the fibre matrix structure, thereby improving the available nutrient utilization and, concomitantly, the performance of growing pigs.

Controlled fermentation is an attractive option for preserving high moisture by-products. Liquid feeding involves the use of a diet prepared from a mixture of liquid food industry by-products and conventional dry materials, or from dry raw materials mixed with water in varying proportions (Missotten et al., 2015). Canibe & Jensen (2003) defined fermented liquid feed (FLD) as a mixture of feed and water stored in a tank at a certain temperature and for a certain time before it is fed to the animals. A fermented liquid diet lowers stomach pH through increased lactic acid concentration and helps to decrease populations of pathogens such as E. coli and Salmonella spp. (Urriola et al., 2010); an FLD improves the nutritional value of the feed (Carlson & Poulsen, 2003; Lyberg et al., 2006).

Pigs do not produce enzymes that can degrade non-starch polysaccharides (NSP) (Kerr & Shurson, 2013). The lack of enzymatic capacity may be compensated for by supplementing diets with exogenous enzymes. It has been reported that exogenous enzymes improve nutrient digestion in pigs (Kerr & Shurson, 2013) and reduce DM losses in high moisture by-products (Nkosi & Meeske, 2010). The effect of feeding fermented sweet orange peel on carcass quality of broilers was investigated (Oluremi et al., 2010). These authors reported a substantial effect on dressing percentage and concluded that a 30% replacement of maize with naturally-fermented sweet orange peel meal was practicable in a broiler production enterprise. Pigs fed low inclusion levels of fermented liquid potato hash diets treated with or without enzymes had improved feed intake, growth rate, and feed conversion ratio (Thomas et al., 2018). Therefore, fermenting high moisture by-products, such as potato hash, may replace conventional energy-rich feedstuffs, such as yellow maize, in pig diets (Lallo et al., 2003).

Therefore, it is necessary to investigate the use of liquid fermentation to improve the utilization of nutrients from potato hash and the subsequent effect on carcass characteristics. Dose-response trials were conducted to accurately determine the optimum inclusion levels of liquid-fermented potato hash in pig diets without adversely affecting carcass performance. Thus, the objective of the study was to determine the carcass characteristics of pigs fed a liquid-fermented potato hash diet. It was hypothesized that inclusion levels of liquid-fermented potato hash feed would have no effect on the carcass characteristics of growing pigs.

 

Materials and Methods

The experiment was carried out under the approbation and guidelines of the Agricultural Research Council Animal Ethics Committee (Reference Number: APIEC16/005). The study was conducted at the Agricultural Research Council (ARC), Animal Production Irene, South Africa. The institute lies at about 25° 34' 0" S and 28° 22' 0" E and is 1526 m above sea level, with an average annual temperature of 18.7 °C.

Potato hash was collected from Simba, a local food-producing company in South Africa and was made of potato peels (largest portion), rejected raw potatoes, and small quantities of yellow maize. Forty-two crossbred. male Large White * Landrace pigs aged 55 d with average weight of 25.5 ± 3 kg (mean ± standard deviation, SD) were randomly selected from the ARC pig herd in Irene. Pigs were housed individually in 1.54 m × 0.8 m pens in an environmentally-controlled house with the temperature of 22-25 °C. The housing facility was cleaned thoroughly and disinfected a week before the trial was undertaken. The temperature and relative humidity in the experimental house were maintained at 24.5 ± 1.9 °C and 62.7 ± 15.07 % (mean ± SD), respectively.

Six pigs were assigned in a completely randomized design to each of six experimental diets and a control. The seven diets were formulated to be isoenergetic and isonitrogenous. The dietary treatments included a dry standard feed; liquid-fermented standard feed; liquid-fermented potato hash, 200 g/kg (as fed), with or without enzymes; and liquid-fermented potato hash, 400 g/kg (as fed), with or without enzymes. Diets were formulated to provide 14 MJ/kg digestible energy (DE), 180 g crude protein (CP)/kg, and 11.6 g lysine /kg which meet and exceed the requirements of growing pigs (NRC, 2012). The experiment lasted for 56 days. An environmental, facility, and dietary acclimatization period of seven days was allowed for pigs before data collection commenced. Diets were prepared in quantities sufficient to feed pigs for a week to prevent spoilage. Feed was supplied ad libitum and water was always available through nipple drinkers. Ingredients and calculated nutrient analysis (g/kg as fed basis) of experimental diets are shown in Table 1.

The back-slopping fermentation approach was followed, as described by Plumed-Ferrer and Von Wright (2009) to ferment diets. Liquid-fermented diets were prepared by mixing formulated diets with water at a ratio of 1:2 for 12 h. The liquid-fermented mixture were stored in a closed 100 L drum under agitation at 25 °C. After 12 h, 50 % of the content was taken out and replaced in the drum with an equal amount of fresh feed and water. Diet samples were taken from the drum weekly after fermentation and kept in a cool dry place until they were homogenized and subsampled for chemical and physicochemical analyses. The experimental dietary samples and potato hash were analysed in triplicate. The dry matter (DM; ID: 2001.12), ash (ID: 942.05), crude protein (CP; ID: 990.03), and ether extract (EE; ID: 963.15) were analysed following the methods from the Association of Official Analytical Chemists (AOAC, 2005). Neutral detergent fibre (NDF; ID: 7-07-06) and acid detergent fibre (ADF; ID: 08-26-05) were determined according to ANKOM Technology Method (Van Soest et al., 1991). The NDF content was assayed using heat stable α-amylase (Sigma A3306, Sigma Chemical Co., St. Louis, MO, USA). The gross energy (GE) was determined using bomb calorimetry (MS-1000 modular calorimeter, Energy Instrumentation, Centurion, South Africa). The bulk density of the diets and potato hash silage was measured using the water displacement method, as described by Kyriazakis and Emmans (1995). The water holding capacity (WHC) was measured using the centrifugation method as described by Whittemore et al. (2003). Swelling capacity was measured according to Canibe & Bach-Knudsen (2002). The chemical composition and physicochemical properties (g/kg DM feed) of experimental diets are shown in Table 2.

Total anaerobic bacteria such as Lactobacillus sp., E. coli, Salmonella sp., and Clostridium perfringens were determined in triplicate according to the methods of Jensen & Mikkelsen (1998). For microbiological enumeration, liquid feed samples (10 g) were transferred into flasks containing 90 mL of peptone water containing 10.0 g Bacto peptone (Merck 1.07213, Darmstadt, Germany)/L and 1.0 g Tween 80/L. The suspension was then transferred to a plastic bag and homogenised in a stomacher blender (Interscience, St. Nom, France) for 2 min. Then, 10-fold dilutions were prepared in peptone water using the technique of Miller & Wolin (1974) and samples (0.1 mL) were plated on selective media.

The concentration of lactic acid was assayed using the method of Jensen & Mikkelsen (1998) on de Man, Rogosa, and Sharp agar (Merck 1.10660.0500) following anaerobic incubation at 20 °C for 3 d. Enterobacteriaceae were enumerated on McConkey agar (Merck 1.05465.0500) following aerobic incubation at 37 °C for 1 d. Yeasts and moulds were enumerated on malt chloramphenicol/chlortetracycline MCA agar (10 g glucose [Merck 1.08337.1000]/L; 3 g malt extract [Merck 1.05397]/L; 3 g yeast extract [Merck 1.03753]/L; 5 g Bacto peptone [Merck 1.07224]/L; 50 mg chlortetracycline + 50 mg chloramphenicol [SR0177E, Oxoid Ltd, Basingstoke, Hampshire, UK]/L; 15 g agar [Merck 1.01614])/L) following aerobic incubation at 20 °C for 3 d. The pH was determined with a pH meter (Thermo Orion Model 525, Thermo Fisher Scientific, Waltham, MA, USA). The pH was taken at 0, 8, and 24 h in three different weeks in triplicate. The water-soluble carbohydrate (WSC) fraction was determined using the phenol-sulphuric acid method. Lactic acid (LA) content was determined using the colorimetric method of Pryce (1969). Samples were taken in three different batches after 8 h of incubation. Table 3 shows the microbial characteristics of the liquid-fermented potato hash diets.

The final average body weight of pigs was 67.7 ± 8.7 kg at the end of the growth performance period. Pigs were weighed prior to slaughtering, fasted for 12 h, then transported in the early hours (07:30) of the morning to the ARC-Irene abattoir, where they were provided with fresh drinking water, kept calm, and then slaughtered. At the abattoir, standard pre-slaughtering procedures were followed. Each pig was electrically stunned with an electrical stunner set at 220 V and 1.8 A with a current flow for 6 s. Electrical stunner electrodes were positioned at the base of each ear. Exsanguination followed within 10 s of stunning. Dehairing and evisceration were done according to the abattoir's standard operating procedures. Warm carcass weight (WCW) was measured after dressing using an overhead scale.

Dressing percentage (DP) was determined from the warm carcass weight as a percentage of live weight. Carcasses were then placed in a cold room, kept at an approximate temperature of 0 °C for 24 h after which cold carcass weights (CCW) were measured. The head from each carcass was removed at the atlanto-occipital joint; the tail was removed at the junction of the third and fourth sacral vertebrae; and the flare fat, kidneys, kidney fat, glands, and remaining parts of the diaphragm were also removed. Carcasses were then split into two parts along the median plane from the remaining sacral vertebra to the first cervical vertebra with a carcass-splitting band saw. Carcass length (CL) was measured from the first rib to the pubic bone using a measuring tape. Backfat measurements were taken at first rib (DFT1), last rib (DFT2), and last lumbar vertebra (DFT3). All other carcass measurements were taken from the left side. A cut was made between the l0^th and 11^th ribs and carried on through the spinal column. The fat measurement at 65 mm from the mid-dorsal line at the last rib (P2) was taken on each carcass with Vernier callipers over the eye muscle, 60 mm from the carcass midline.

Eye muscle length (EML) and three measurements of the eye muscle width (EMW) were taken from the cut interface. Lean meat percentage (Lean %) was calculated using the formula of Bruwer (1992):

where V is the fat thickness (mm), and S is the muscle depth (mm).

The eye muscle area (EMA) was estimated using the formula of Zhang et al. (2007):

where EMW is the average of the three width measurements of the eye muscle.

From the same cut where the P2 measurements were taken, a sample joint measuring 2.5 cm thick and 16 cm long, measured along the surface of the back of the eye muscle, was cut out and weighed. This sample joint was placed in a nylon bag and inserted in a small plastic bag to prevent the sample joint from touching the bottom of the plastic bag. They were then stored in a refrigerator between 0 and 5 °C for 24 h. Afterward, the drip loss was calculated as:

The measurements for hindquarter length (HQL), hindquarter length circumference (HQC), and rip weight proportion (RWP), shoulder weight proportion (SWP), and hindquarter weight proportion (HQWP) were carried out according to the method of Kanengoni et al. (2014).

Data for microbial characteristics of the feed, and carcass traits of growing pigs fed on fermented liquid potato hash diets treated with or without enzyme were analysed using the General Linear Model of procedures of SAS (2008).

The model used was:

where:

Y_ijkl is the microbial characteristics of feed and carcass traits

μ is the overall mean response common to all observations

α_i is the effect of liquid fermentation

β_j is the effect of inclusion of liquid-fermented potato hash with or without enzymes (α_i × β_j)

ε_ijki is the residual error.

 

Results

Microbial characteristics of liquid-fermented potato hash diets with or without enzymes are shown in Table 3. Lactic acid bacteria (LAB), Enterobacteriaceae, yeast and moulds, and E. coli in liquid-fermented diets with or without potato hash inclusion were influenced by the addition of enzymes (P <0.05). The low and high liquid-fermented potato hash diets with enzymes had higher LAB, Enterobacteriaceae, yeast and moulds, and E. coli levels than the low and high liquid-fermented potato hash diets without enzymes (p <0.05). An effect of diet and enzyme was observed on lactic acid and water-soluble carbohydrates (p <0.05). There was no interaction between diets and enzymes on lactic acid and water-soluble carbohydrate concentration between the treatments. The pH of the three batches at 0 h did not differ between the inclusion levels of fermented liquid potato hash with or without enzyme (p >0.05). The low and high liquid-fermented potato hash diets without enzymes had a higher pH than the low and high liquid-fermented potato hash diets with enzymes at 8 and 24 h (p <0.05).

Carcass traits of Large White × Landrace pigs fed diets containing different inclusion levels of liquid-fermented potato hash with or without enzyme are shown in Table 4. There was a difference in DL, lean percentage, eye muscle area (EMA), back fat (BF), and back fat thickness (P2) among the diets provided to pigs (P <0.05). A control and fermented control diet had similar low drip loss and lean percentage (p <0.05). Fermented potato hash with or without enzyme led to a higher drip loss and lean percentage (P <0.05). Pigs fed the control and high liquid-fermented diets had a smaller EMA than the other diets (P <0.05). The control and liquid-fermented control diets had a higher back fat than other treatments (P <0.05). There were no differences in warm carcass, cold carcass weights, dressing percentage, carcass length, and shoulder fat between the treatments (P >0.05). There was no interaction between diet and enzyme on carcass traits (p >0.05). Primary pork cuts of Large White × Landrace pigs fed diets containing different inclusion levels of liquid-fermented potato hash with or without enzyme are shown in Table 5. There was an effect of diets on rib weight proportion (RWP) and ham circumference (HC) in pigs (P <0.05). Pigs fed fermented diets that contained potato hash and fermented control diets with enzyme had good RWP, but greater values were observed on low liquid-fermented potato hash diets (p <0.05). Other primary pork cuts were similar between the diets (p >0.05). There was no diet × enzyme interaction for primary pork cuts in pigs (p >0.05).

 

Discussion

Food fermentation is one of the oldest ways of food processing and preservation. As expected, fermented liquid potato hash diets treated with enzymes had low enteropathogens (Beal et al., 2005). Lactic acid (LA) is the strongest of all liquid-fermented dietary acids and its presence will drop pH more effectively than volatile fatty acids (McDonald et al., 2010). The same was true in the current study, which recorded a lower pH (<3.6) and higher LA levels on fermented liquid potato with enzymes. The pH and LA can be associated with an increase in fermentable carbohydrates by hydrolysis of the cell wall, which increases fermentation by LAB. Water-soluble carbohydrates are regarded as essential substrates for the growth of LAB for proper fermentation (McDonald et al., 2010), and low levels may restrict LAB growth. A low pH indicates that the fermented-liquid potato hash diets were well-preserved. It is well-documented that one of the most important factors affecting LFD quality is the rate of decrease in pH of the material being preserved (Moran et al., 2006).

The increase in pH during the first hours of incubation was probably due to the acid binding capacity of the dietary ingredients (Scholten et al., 2001a). All diets showed a drop in pH after 8 to 24 h of fermentation. The decreasing counts of Enterobacteriaceae in the liquid-fermented potato diets followed a pattern previously observed by Canibe & Jansen (2003). In the present study, the counts of yeasts during fermentation of liquid feed were lower than previously observed (Geary et al., 1999). Similar to Nadeau et al. (2000), the present study demonstrated an improved sugar content in cellulose of fermented potato hash diet treated with enzymes.

Feeding fermented liquid feed to pigs has been proposed as an approach to maintain high and regular feed and water intake. It has also been shown to decrease the incidence of diarrhoea (Højberg et al., 2003) and pig dysentery (Lindecrona et al., 2000), as well as the spread of zoonoses to the consumers (Brooks et al., 2003) compared with dry feed. Brooks et al. (2003) reported that fermented cereal grains could decrease the pH value and improve the palatability of fermented liquid feed.

High fibre diets increase the weight of visceral organs in pigs (Montagne et al., 2003). Diets containing different inclusion levels of fermented liquid potato hash with or without enzyme did not have a lower DP, as expected. This concurs with studies done on potato hash silage (Ncobela et al., 2018) and potato chip scraps (Borton & Rahnema, 1998). Pigs fed low and high fermented-liquid potato hash with or without enzyme had greater drip loss values than pigs fed the control or fermented-liquid control diets with or without enzyme. Drip loss (DL) of pork fed high moisture diets is affected by numerous and complex factors, including rate of pH decline and ultimate pH, presence of the halothane gene, and transportation (Fischer, 2007). Although drip loss is of economic importance, the mechanism behind this phenomenon has not been adequately studied (Otto et al., 2007). Because the high fermented-liquid potato hash with or without enzyme had a greater ultimate pH, the DL results contradict the assertion by Huff-Longergan et al. (2002) that a higher ultimate pH is associated with better water holding capacity, translating into lower drip losses during storage.

Experimental diets did not influence the length of the carcass in the study. Carcass length affects the weight of the most valuable meat cuts (Poto et al., 2007) and determines the amount of rashers of back bacon obtained (Kanengoni et al., 2014). English et al. (1988) stated that carcass weight and the genotype of the pig largely influence CL. The control and fermented-liquid control diets with or without enzyme had more subcutaneous fat than the low and high liquid-fermented potato hash diets with or without enzyme; this was demonstrated by a lower lean percentage. Different inclusions of fermented liquid potato hash with or without enzymes reduced back-fat measurements. Back-fat thickness, P2, and shoulder fat measures were lower on the fermented-liquid potato hash diets with or without enzyme, compared to the control and fermented-liquid control diets. Inclusions of liquid-fermented potato hash diets with or without enzyme, however, did not negatively affect some commercially important pork cut measurements of the hindquarter, ham length, and shoulder. The hindquarter length, circumference, and weight and the shoulder weight measures were affected mainly by diet.

Nyachoti et al. (2004) reported that replacing non-fibrous ingredients with bulky feedstuffs limited intake. The feed with a high inclusion of liquid-fermented potato hash treated with or without enzyme had a higher NDF and was bulkier. The reduced carcass performance in the high liquid-fermented potato hash diets, with or without enzymes, suggests that high NDF content in the diet compromised carcass performance in pigs. Considering that CP was low in diets with high liquid-fermented potato hash, the effect of CP was likely to have been confounded with NDF and CF content of these feeds. Evidence exists that an average of 31% of protein in commonly used fibre sources is bound to the NDF and is not available for the pig (Bindelle et al., 2005). In the current study, the enzymes consisted of xylanase, amylase, and protease, which targeted substrates such as NSP, indigestible starch, and protein. In the experiment of Kim et al. (2003), the enzymes used were p-1,4-mannanase, p-1,4-mannosidase, and p-1,6-galactosidase, which only targeted NSPs. Enzyme supplementation improved the digestibility of gross energy, crude protein, and dry matter. This result is consistent with previous findings (Olukosi et al., 2007).

 

Conclusions

The use of the liquid fermentation method to preserve and improve utilization of industrial byproducts is a promising approach. It can be concluded from this study that enzyme-treated diets had good microbial quality, which suggests that the liquid-fermented potato hash was properly preserved. The addition of enzyme to liquid-fermented potato hash increased lactic acid production and decreased pH. Liquid-fermented potato hash reduced backfat thickness. Pigs fed less fermented-liquid potato hash, with or without enzymes, had improved carcass traits. The influence of liquid-fermented potato hash on other carcass measurements was not definitive.

 

Funding

The authors sincerely thank Agricultural Research Council of South Africa for funding this project.

 

Contributions made by authors

RST & MC conceived project. RST, CN, & PS conducted experiments. CN & VH analysed data and wrote the manuscript. MC edited and improved the manuscript. All authors read and approved the manuscript.

 

Data and material availability

The data are available from the corresponding author on request

 

Consent to participate

Authors agreed upon the roles and responsibilities taken towards one another throughout the study

 

Conflict of interest

The authors declare that they have no conflict of interest.

 

Consent for publication

Authors grant the publisher the sole and exclusive license of the full copyright

 

References

AOAC, 2005. Official Methods of Analysis, 18th ed. AOAC International, Gaithersburg.         [ Links ]

Beal, J.D., Niven, S.J., Brooks, P.H., Gill, B.P., 2005. Variation in short chain fatty acid and ethanol concentration resulting from the natural fermentation of wheat and barley for inclusion in liquid diets for pigs. J. Sci. Food Agric. 85, 433-440.         [ Links ]

Bindelle, J., Leterme, P. & Buldgen, A., 2008. Nutritional and environmental consequences of dietary fibre in pig nutrition: A review. Biotech. Agron. Soc. Env. 12, 69-80.         [ Links ]

Borton, R. J., Rahnema, S., 1998. Carcass characteristics for swine fed potato chip scraps. J. Ani. Sci. 76 (Suppl. 1), 147 (Abstr).         [ Links ]

Brooks, P.H., 2008. Fermented liquid feed for pigs. CAB Rev. Perspect. Agric. Vet. Sci. Nutr. Nat. Resour. 3, 1 -18.         [ Links ]

Bruwer, G.G., Heinze, P.H., Zondagh, I.B. & Naude, R.T., 1991. The development of a new classification system for pig carcasses in the RSA. Porcus. Dec/Jan, 27-31.         [ Links ]

Canibe, N. & Bach-Knudsen, K. E., 2002. Degradation and physicochemical changes of barley and pea fibre along the gastrointestinal tract of pigs. J. Sci. Food Agric, 82, 27-39. DOI.org/10.1002/jsfa.985        [ Links ]

Canibe, N. & Jensen J, B.B., 2003. Fermented and nonfermented liquid feed to growing pigs: Effects on aspects of gastrointestinal ecology and growth performance. J. Anim. Sci. 81, 2019-2031. DOI: 10.2527/2003.8182019x        [ Links ]

Carlson, D. & Poulsen, H.D., 2003. Phytate degradation in soaked and fermented liquidfeed-effect of diet, time of soaking, heat treatment, phytase activity, pH, and temperature. Anim. Feed Sci. Technol. 103, 141-154. DOI.org/10.1016/S0377-8401 (02)00288-2        [ Links ]

English, P. R., Fowler, V. R., Baxter, S., Smith. B. 1988. The growing and finishing pig: Improving Efficiency 2nd Edition. Farming Press Books, Ipswich.         [ Links ]

Fischer, K., 2007. Drip loss in pork: Influencing factors and relation to further meat quality traits. J. Anim Breed. Genet. 124, 12-18. DOI: 10.1111/j.1439-0388.2007.00682.x        [ Links ]

Geary, T.M., Brooks, P.H., Beal, J.D., Campbell, A., 1999. Effect on weaner pig performance and diet microbiology of feeding a liquid diet acidified to pH 4 with either lactic acid or through fermentation with Pedicoccus acidilactici. J. Sci. Food Agric. 72, 17-24.         [ Links ]

Højberg, O., Canibe, N., Knudsen, B., Jensen, B.B., 2003. Potential rates of fermentation in digesta from the gastrointestinal tract of pigs: Effect of feeding fermented liquid feed. Appl. Environ. Microbiol. 69, 408-418.         [ Links ]

Huff-Longergan, E., Baas, T.J., Malek, M., Dekkers, J.C. M., Prusa, K., Rothschild. M.F., 2002. Correlations among selected pork quality traits. J. Anim. Sci. 80, 617-627.         [ Links ]

Jensen, B.B., Mikkelsen, L.L.,1998. Feeding liquid diets to pigs. In: P. C. Garnsworthy and J. Wiseman (Ed.) Recent Advances in Animal Nutrition. Nottingham University Press, pp. 107-126.         [ Links ]

Kanengoni, A.T., Chimonyo, M., Erlwanger, K.H., Ndimba, B.K. & Dzama, K., 2014. Growth performance, blood metabolic responses, and carcass characteristics of grower and finisher South African Windsnyer-type indigenous and Large White × Landrace crossbred pigs fed diets containing ensiled corncobs. J. Anim. Sci. 92, 5739-5748. DOI: 10.2527/jas.2014-8067        [ Links ]

Kerr, B.J., Shurson, G.C., 2013. Strategies to improve fiber utilization in swine. J. Anim. Sci. Biotechnol. 4, 11. Doi: 10.1186/2049-1891-4-11.         [ Links ]

Khedkar, R., Singh, K., 2018. Food Industry Waste: A panacea or pollution hazard? In: Jindal, T. (Ed.) Paradigms in Pollution Prevention. Springer Briefs in Environmental Science. Springer, Cham. https://doi.org/10.1007/978-3-319-58415-7_3        [ Links ]

Kim, H.Y., Song, Y.M., Jin, S.K., Kim, I.S., Kang, Y.S., Lee, S.D., Chowdappa, R., HA, J.H., Kang, S.M., 2006. The effect of change in meat quality parameters on pig Longissimus dorsi muscle by the addition of fermented persimmon shell diet. Asian Australasian J. Anim. Sci. 19, 286-291.         [ Links ]

Kyriazakis, I.& Emmans, G.C., 1995. The voluntary feed intake of pigs given feeds based on wheat bran, dried citrus pulp, and grass meal in relation to measurements of bulk. Br. J. Nutr. 73, 191-208. DOI: 10.1079/bjn19950023        [ Links ]

Lallo, F. H., do Prado, I. N., do Nascimento, W. G., Zeoula, L.M., Moreira, F.B., Wada, F.Y., 2003. Substitution levels of corn silage by pineapple by-products on ruminal degradability in beef cattle. R. Bras. Zootec. 32, 719-726. DOI: 10.1590/S1516-35982003000300024        [ Links ]

Lindecrona, R. H., Jensen, B. B. Leser, T. K. M0ller., K., 2000. The influence of diet on the development of swine dysentery. Proceedings of the 16th International Pig Veterinary Society Congress, Melbourne, Australia. Pp 7.         [ Links ]

Lyberg, K., Lundh, T., Pedersen, C., Lindberg, J.E., 2006. Influence of soaking, fermentation and phytase supplementation on nutrient digestibility in pigs offered a grower diet based on wheat and barley. Anim. Sci. 82, 853-858.         [ Links ]

McDonald, P., Edwards, R.A., Greenhalgh, J.F.D., Morgan, C.A., Sinclair, L.A., Wilkinson, R.G., 2010. Chapter 19: Silage. In: Animal Nutrition, 7^th Ed. pp. 499-520.         [ Links ]

Missotten, J. A., Michiels, J., Degroote, J. & De Smet, S., 2015. Fermented liquid feed for pigs: An ancient technique for the future. J. Anim. Sci. Biotechnol. 6, 1-9. doi.org/10.1186/2049-1891-6-4        [ Links ]

Montagne, L., Pluske, J., Hampson, D., 2003. A review of interactions between dietary fibre and the intestinal mucosa, and their consequences on digestive health in young non-ruminant animals. Anim. Feed Sci. Technol. 108, 95-117.         [ Links ]

Nadeau, E.M., Russell, J.R., Buxton, D.R. 2000. Intake, digestibility, and composition of orchard grass and alfalfa silages treated with cellulase, inoculant, and formic acid fed to lambs. J. Anim. Sci. 78, 2980-2989.         [ Links ]

Ncobela, C. N., Kanengoni, A. T., Chimonyo, M., Hlatini, V. A., 2021. Responses in apparent total digestibility, rate of passage, growth performance, and physicochemical properties of the digesta of Windsnyer pigs fed on increasing levels of potato hash silage. Anim. Biosci. DOI: 10.5713/ab.21.0358        [ Links ]

Ncobela, C. N., Kanengoni, A. T., Hlatini, V. A., Thomas, R. S., Chimonyo, M., 2017. A review of the utility of potato by-products as a feed resource for smallholder pig production. Anim. Feed Sci. Technol. 227, 107-117.         [ Links ]

Ncobela, C.N., Kanengoni, A.T., Thomas, R.S., Chimonyo, M., 2018. Voluntary feed intake and growth performance of slow-growing pigs fed on increasing levels of ensiled potato hash meal. Trop. Anim. Health. Prod. 50, 113-120. DOI: 10.1007/s11250-017-1410-9        [ Links ]

Nkosi, B.D., Meeske, R., 2010. Effects of whey and molasses as silage additives on potato hash silage quality and growth performance of lambs. S. Afr. J. Anim. 40, 229-237. DOI: 10.4314/sajas.v40i3.7        [ Links ]

Nyachoti, C.M., Zijlstra, R.T., de Lange, C.F.M., Patience, J.F., 2004. Voluntary feed intake in growing-finishing pigs: A review of the main determining factors and potential approaches for accurate predictions. Can. J. Anim. Sci. 84, 549-566.         [ Links ]

Olukosi, O., Bedford, M., Adeola, O. 2007. Xylanase in diets for growing pigs and broiler chicks. Can. J. Anim. Sci. 87, 227-235.         [ Links ]

Oluremi, O.I.A., Ebe, A.I., Ngi, J., Aku, E.O., 2010. Effect of naturally fermented sweet orange (Citrus sinensis) peel meal on its maize replacement valuein broiler diet on performance and carcass indices. Proc. 35th Annu. Conf., Nig. Soc. for Anim. Prod. 14-17 March. Univ. of Ibadan. Nigeria. pp. 449-542.         [ Links ]

Otto, G., Roehe, R., Looft, H., Thoelking, L., Knap, P.W., Rothschild, M.F., Plastow, G.S., Kalm, E., 2007. Associations of DNA markers with meat quality traits in pigs with emphasis on drip loss. Meat Sci. 77, 185-195.         [ Links ]

Plumed-Ferrer C., Von Wright, A., 2009. Fermented pig liquid feed: Nutritional, safety, and regulatory aspects. J. Appl. Microbiol. 106, 351-368. DOI: 10.1111/j.1365-2672.2008.03938.x        [ Links ]

Poto, A., Galian, M., Peinado, B., 2007. Chato Murciano pig and its crosses with Iberian and Large White pigs, reared outdoors. Comparative study of the carcass and meat characteristics. Livest. Sci.111, 96-103        [ Links ]

Pryce, J.D., 1969. A modification of the Barker-Summerson method for the determination of lactic acid. Analyst, 94(1125), 1151 -1152.         [ Links ]

SAS, 2008. SAS User's Guide: Statistics, Version 9.3. SAS Institute, Cary, NC, USA.         [ Links ]

Scholten, R.H., van der Peet-Schwering, C.M., Verstegen, M.V.A., den Hartog, L.A., Schrama, J.W., Vesser, P.C., 1999. Fermented co-products and fermented compound diets for pigs: A review. Anim. Feed Sci. Technol., 82, 1-19. doi.org/10.1016/S0377-8401(99)00096-6        [ Links ]

Thomas, R.S., Kanengoni, A.T., Chimonyo, M., 2018. Impact of fermented liquid potato hash diets on growth performance of grower pigs. J. Agric. Sc. 10(6).         [ Links ]

Urriola, P. E., Shurson, G.C., Stein, H.H., 2010. Digestibility of dietary fiber in distillers' coproducts fed to growing pigs. J. Anim. Sci. 88, 2373-2381.         [ Links ]

Whittemore, E.C., Emmans, G.C., Kyriazakis, I., 2003. The relationship between live weight and the intake of bulky foods in pigs. Anim. Sc. 76, 89-100. DOI: https://doi.org/10.1017/S1357729800053352        [ Links ]

Zhang, H.J., Xiong, Z.Y., Zuo, B., Lei, G.M., Jiang, W.S., Li, E.F., Zheng, R.L., Li, J., Xu, Q.D., 2007. Quantitative trait loci for carcass traits on pig chromosomes 4, 6, 7, 8, and 13. J. Appl. Genet. 48, 363-366. DOI: 10.1007/BF03195233        [ Links ]

 

 

Submitted 29 August 2022
Accepted 22 June 2023
Published 25 October 2023

 

 

# Author deceased
* Corresponding author: Michael.chimonyo@univen.ac.za